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  • Security and the Mobile Workforce

    - by tobyehatch
    Now that many organizations are moving to the BYOD philosophy (bring your own devices), security for phones and tablets accessing company sensitive information is of paramount importance. I had the pleasure to interview Brian MacDonald, Principal Product Manager for Oracle Business Intelligence (BI) Mobile Products, about this subject, and he shared some wonderful insight about how the Oracle Mobile Security Tool Kit is addressing mobile security and doing some pretty cool things.  With the rapid proliferation of phones and tablets, there is a perception that mobile devices are a security threat to corporate IT, that mobile operating systems are not secure, and that there are simply too many ways to inadvertently provide access to critical analytic data outside the firewall. Every day, I see employees working on mobile devices at the airport, while waiting for their airplanes, and using public WIFI connections at coffee houses and in restaurants. These methods are not typically secure ways to access confidential company data. I asked Brian to explain why. “The native controls for mobile devices and applications are indeed insufficiently secure for corporate deployments of Business Intelligence and most certainly for businesses where data is extremely critical - such as financial services or defense - although it really applies across the board. The traditional approach for accessing data from outside a firewall is using a VPN connection which is not a viable solution for mobile. The problem is that once you open up a VPN connection on your phone or tablet, you are creating an opening for the whole device, for all the software and installed applications. Often the VPN connection by itself provides insufficient encryption – if any – which means that data can be potentially intercepted.” For this reason, most organizations that deploy Business Intelligence data via mobile devices will only do so with some additional level of control. So, how has the industry responded? What are companies doing to address this very real threat? Brian explained that “Mobile Device Management (MDM) and Mobile Application Management (MAM) software vendors have rapidly created solutions for mobile devices that provide a vast array of services for controlling, managing and establishing enterprise mobile usage policies. On the device front, vendors now support full levels of encryption behind the firewall, encrypted local data storage, credential management such as federated single-sign-on as well as remote wipe, geo-fencing and other risk reducing features (should a device be lost or stolen). More importantly, these software vendors have created methods for providing these capabilities on a per application basis, allowing for complete isolation of the application from the mobile operating system. Finally, there are tools which allow the applications themselves to be distributed through enterprise application stores allowing IT organizations to manage who has access to the apps, when updates to the applications will happen, and revoke access after an employee leaves. So even though an employee may be using a personal device, access to company data can be controlled while on or near the company premises. So do the Oracle BI mobile products integrate with the MDM and MAM vendors? Brian explained that our customers use a wide variety of mobile security vendors and may even have more than one in-house. Therefore, Oracle is ensuring that users have a choice and a mechanism for linking together Oracle’s BI offering with their chosen vendor’s secure technology. The Oracle BI Mobile Security Toolkit, which is a version of the Oracle BI Mobile HD application, delivered through the Oracle Technology Network (OTN) in its component parts, helps Oracle users to build their own version of the Mobile HD application, sign it with their own enterprise development certificates, link with their security vendor of choice, then deploy the combined application through whichever means they feel most appropriate, including enterprise application stores.  Brian further explained that Oracle currently supports most of the major mobile security vendors, has close relationships with each, and maintains strong partnerships enabling both Oracle and the vendors to test, update and release a cooperating solution in lock-step. Oracle also ensures that as new versions of the Oracle HD application are made available on the Apple iTunes store, the same version is also immediately made available through the Security Toolkit on OTN.  Rest assured that as our workforce continues down the mobile path, company sensitive information can be secured.  To listen to the entire podcast, click here. To learn more about the Oracle BI Mobile HD, click  here To learn more about the BI Mobile Security Toolkit, click here 

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  • Online Storage and security concerns

    - by Megge
    I plan to set up a small fileserver. I already own a small server at HostEurope (VirtualServer L, 250GB space), but they don't offer enough space (there is the HostEurope Cloud, but paying for bandwidth isn't an option here, video-streaming should be possible) Requirements summarized: Storage: 2TB, Users: ~15, Filesizes: < 100GB, should be easily reachable (Mount as a networkdrive or at least have solid "communication" software) My first question would be: Where can I get halfway affordable online storages? And how should I connect them to my server? Getting an additional server is a bit overkill, as I know no hoster which allows 2 TB on a small 2 Ghz Dual Core 2 GB RAM thingy (that would be enough by far, I just need much space), and connecting it via NFS or FTP over Internet seems a bit strange and cripples performance. Do you have any advice where I could get that storage service from? (I sent HostEurope a custom request today, but they didn't answer till now. If they can provide me with that space, this question will be irrelevant, but the 2nd one is the more important one anway, don't do much more than recommend me some based on experience, you don't have to crawl hours through hosting services) livedrive for example offers 5 TB for 17€ / month, I'd be happy with 2 TB for 20 €, the caveat is: It doesn't allow multiple users, which leads me to my second question: Where are the security problems? Which protocol is sufficient (I want private and "public" folders etc. the usual "every user has its own and a public space"-thing), secure and fast? (I'd tend to (S)FTP, problem with FTP is: Most of those hosting services don't even allow FTP with mutliple users and single users lead me into "hacking" a solution (you could map the basic folder structure on the main server and just mount every subfolder from the storage, things get difficult with a public folder with 644 permissions though) Is useing something like PKI or 802.1X overkill for private uses?

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  • Mac Management and Security

    - by Bart Silverstrim
    I was going through some literature on managing OS X laptops and asked someone some questions about usage scenarios when using the MacBooks. I asked someone more knowledgeable than I about whether it was possible for my Mac to be taken over if I were visiting another site for a conference or if I went on a wifi network at a local coffee house with policies from an OS X Server with workgroup manager (either legit for the site or someone running a version of OS X Server on hardware they have hidden somewhere on the network), which apparently could be set up to do things like limit my access to Finder or impose other neat whiz-bang management features. He said that it is indeed possible for it to happen as it would be assigned via the DHCP server and the OS X server would assume my Mac is a guest and could hand out restrictions and apparently my Mac will happily accept them without notifying me or giving me an option, unlike Windows which I believe would need to be joined to a domain before it becomes "managed" by Active Directory. So my question is as network admins and sysadmins with users traveling with MacBooks, is there a way to reasonably protect your users from having their machines hijacked without resorting to just turning off networking all the time? Or isn't this much of a security hazard? What threat does this pose to the road warriors in your businesses?

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  • Managing Apache to Compensate for WebDAV's Security Masking

    - by Tohuw
    When a user creates a file via WebDAV, the default behavior is that the file is owned by the user and group running the Apache process, with a umask of 022. Unfortunately, this makes it impossible for unprivileged users to write to the files by other means without being a member of the group Apache runs under (which strikes me as a particularly bad idea). My current solution is to set umask 000 in Apache's envvars and remove all world permissions from the webdav parent directory for the user. So, if the WebDAV share is /home/foo/www, then /home/foo/www is owned by www-data:foo with permissions of 770. This keeps other unprivileged users out, more or less, but it's hokey at best and a security disaster awaiting at worst. From my research and poking around at mod_dav and Apache, I cannot find a reasonable solution short of a cron job flipping all the permissions back (I'd rather not have the load and increased complexity on the server). SuExec won't work, either, because WebDAV operations are not going to execute as a different user. Any thoughts on this? Thank you.

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  • Mac Management Without Permission and Security

    - by Bart Silverstrim
    I was going through some literature on managing OS X laptops and asked someone some questions about usage scenarios when using the MacBooks. I asked someone more knowledgeable than I about whether it was possible for my Mac to be taken over if I were visiting another site for a conference or if I went on a wifi network at a local coffee house with policies from an OS X Server with workgroup manager (either legit for the site or someone running a version of OS X Server on hardware they have hidden somewhere on the network), which apparently could be set up to do things like limit my access to Finder or impose other neat whiz-bang management features. He said that it is indeed possible for it to happen as it would be assigned via the DHCP server and the OS X server would assume my Mac is a guest and could hand out restrictions and apparently my Mac will happily accept them without notifying me or giving me an option, unlike Windows which I believe would need to be joined to a domain before it becomes "managed" by Active Directory. So my question is as network admins and sysadmins with users traveling with MacBooks, is there a way to reasonably protect your users from having their machines hijacked without resorting to just turning off networking all the time? Or isn't this much of a security hazard? What threat does this pose to the road warriors in your businesses?

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  • Microsoft Security Essentials & MsMpEng.exe hogging resources

    - by Mike
    I've been using MSE for a couple months now, never had a single problem. All of a sudden the process "MsMpEng.exe" will randomly go crazy and hog all my system resources so I can't do anything unless I kill it in the task manager. (I've quit the program for now and my comp is running smooth). When I restart the program, reboot, whatever, it goes off and hogs all the resources again after a couple minutes. If I kill the process it will go away and then come back a couple minutes later and do the same thing. I've scanned with MSE, another antivirus and malware with no probs. Any ideas? Should I uninstall and find something else? The thing is I've liked it so far. I'm running Win7 64-bit. Also, I'm not running any other conflicting security programs. This is the only one on my PC right now. Windows Defender is also off.

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  • Resources for Smartphone Security

    - by Shial
    My organization is currently working on improving our data and network security due to increasing HIPAA laws and a general need to get a better grasp on controlling our health related information. We are a non-profit working with people with developmental disabilities so we handle a lot of medical related information. One area that has been identified as a risk is our use of smartphones, specifically at this time Windows Mobile 6.1 devices from T-Mobile. We do not utilize the VPNs on the phones so there isn't any way they can access our databases or file servers (username/password for VPNs is not the domain logons). What would be exposed however is the particular user's email account since you could extract out the username/password and access the email either on the device or on our web email (Exchange 2003) which could contain HIPAA protected confidential information about clients and services and this would be an incident that would have to be reported. What resources or ideas would help us secure these devices? I'm not worried about data interception (using SSL) but more about physical theft or loss of the device. Are there websites that I just have not found with guidelines and suggestions or particualar products that would help protect us? I also don't want to limit the discussion to windows Mobile either. I myself am looking at an android 2.0 device and there is always the eventual possibility we could get pushed to enable the VPNs. I know this is a subject that likely won't have any particular correct answer and it is something we should all be aware of since there devices are sitting outside of our immediate control most of the time.

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  • Securing SSH/SFTP and best practices on security

    - by MultiformeIngegno
    I'm on a fresh VPS with Ubuntu Server 12.04. I wanted to ask you the good practices to apply to enhance security over a stock Ubuntu-server. This is what I did up to now: I added Google Authenticator to SSH, then I created a new user (whom I'll use instead of 'root' for SSH & SFTP access) which I added to my /etc/sudoers list below 'root', so now it's: # User privilege specification root ALL=(ALL:ALL) ALL new_user ALL=(ALL:ALL) ALL Then I edited sshd_config and set PermitRootLogin to 'no'. Then restarted the ssh service. Is this ok? There are a few things I'd like to ask you though: 1) What's the sense of adding a new (sudoer) user whilst the root user still exist (ok it can't access with root privilege but it's still there..)? 2) System files are owned by 'root'.. I want to use my new_user to access via SFTP but with it I can't edit those files!! Should I mass-CHMOD 'em so that new_user has write perms too? What's the good practice on this? Thanks in advance, I hope you'll tell me if I did something wrong and/or other ways to secure the system. :)

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  • Can I disable this Windows (XP) Security Warning?

    - by FumbleFingers
    I recently reformatted my hard drive and reinstalled Windows XP (I know I'll have to take the plunge and commit to Win8 "real soon, now", but I'm just not quite ready for the upheaval yet! :) I used to use WinRar (and later, when I got fed up with the "nag" messages, 7-Zip), but I haven't installed either of them in my new configuration, so I must be using the built-in XP facility when I open *.zip files. For years, I've been opening downloaded *.zip archives, and using "drag & drop" to copy to a File Explorer window open on the folder where I want the files to end up (usually, My Documents\Downloads). But now I find that when I "drop" the file(s), I get a pop-up Windows Security Warning saying Are you sure you want to copy or move files to this folder? You should only move or copy files from locations that you trust Can anyone explain why I'm getting this message, and is there any (reasonably easy, please! :) way to suppress it? Since I've already put the *.zip file on my computer, it seems a bit late to ask if I trust it. (Thus far, the files in question have always been plain text, so it's not a matter of dodgy programs, etc.) Apologies for the low quality image - I don't have the appropriate tools or knowledge to do any better, and it doesn't help that my "PrtScr" screen capture has included what would have been on my second monitor (TV) if it had been turned on. If you can't read it, trust me - I have copied the text verbatim.

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  • Hiding subfolders from users with Windows Server security

    - by Frans
    Using Windows Server 2008. I would like to allow all users to map to a common network drive and be able to browse it. But, I only want them to be able to see the subfolders they actually have access rights to. Is this doable? Example I have a share with two folders on it; \\domain\share\FolderA \\domain\share\FolderB With three different security groups, I would like to map a network drive for all three to \\domain\share. However, for group1, I want them to only be able to see FolderA, group2 should only see FolderB and group3 should see both. I am not just talking about denying access to the actual folder, which is easy enough, I don't want the user to even be able to see that the folder exists. In other words, when group 1 logs in and do "dir n:\" they should see N:\FolderA When group 2 logs in, they should see N:\FolderB and when group 3 logs in they should see N:\Folder A N:\Folder B My half-baked solution If I completely block access to the root then I can't map a drive to it. I can give everyone the traverse right which then allows the user to map a drive. However, if a member of group1 or group2 tries to go to "N:\" they get an access denied error. If they go to N:\FolderA (for group1) then it works. So, that sort of works, but it would be nicer if the user could actually browse to N:\ and just only see the subfolders they have access to. I am pretty sure I have seen this done but not sure how to do it myself. Any advice would be greatly appreciated.

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  • Windows 2008 server smart card security module problem

    - by chris13work
    Hi, I've got a smart card reader and a server application using it as a security module. If I run it under DOS prompt, everything is fine. The server is running and clients can connect to it. I tried to install the server as window service and start it. The server starts but always gives back authentication error because it cannot call the smart card to do encryption. Then I tried to start it with task scheduler and set the trigger factor as "on startup". The server starts also but still cannot access the smart card reader. Then I tried remote desktop to the machine and run the server application under DOS prompt. Same error is returned. The situation is that the smart card reader only works under active console desktop environment. In the server application, WINSCARD API is used to access the smart card reader. Any suggestion so that we can access the smart card reader in running services? OS: Windows Server 2008 Smart Card Driver: Windows USB smart card Reader Smart Card API: WINSCARD

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  • Windows 2008 server smart card security module problem

    - by chris13work
    Hi, I've got a smart card reader and a server application using it as a security module. If I run it under DOS prompt, everything is fine. The server is running and clients can connect to it. I tried to install the server as window service and start it. The server starts but always gives back authentication error because it cannot call the smart card to do encryption. Then I tried to start it with task scheduler and set the trigger factor as "on startup". The server starts also but still cannot access the smart card reader. Then I tried remote desktop to the machine and run the server application under DOS prompt. Same error is returned. The situation is that the smart card reader only works under active console desktop environment. In the server application, WINSCARD API is used to access the smart card reader. Any suggestion so that we can access the smart card reader in running services? OS: Windows Server 2008 Smart Card Driver: Windows USB smart card Reader Smart Card API: WINSCARD

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  • Webcam security camera software that runs as a service

    - by hurfdurf
    I've been looking for Windows webcam software that will run as a Windows service without any user login. The goal is to use the webcam as a cheap security camera and log the results to secure networked storage (windows share, not FTP). The requirements are: Motion detection Video capture Runs as a service (should start recording immediately after reboot) Nice to have: Round-robin storage, e.g. 10Gb limit, oldest files overwritten/deleted when space gets low I've read the other webcam questions but still haven't stumbled across anything suitable. Evaluations thus far: Title MotionDetect Service Snapshots Video SpaceLimit License Yawcam Yes Yes Yes No No GPL WebCam ZoneTrigger Yes No Yes Yes No Commercial Dorgem Yes No Yes Yes No GPL AbelCam Yes No Yes Yes No Commercial Logitech Yes No Yes Yes No Paired with camera IspyConnect Yes No Yes Yes Yes Free SecureCam (SourcefoYes No Yes Yes No GPL AbelCam Yes No Yes Yes No Commercial Active WebCam Yes Yes(?) Yes Yes Volume Free Commercial WebCam Surveyor Yes No Yes Yes No Commercial WebCamsPy NA NA NA NA NA GPL Camera: Logitech Webcam Pro 9000 Windows 7 32-bit WebCamsPy failed to initialize so couldn't be tested So far, the contenders: Active Webcam comes the closest, and claims to run as a service, but i haven't been able to get it to record after a cold boot even though a service is running. Yawcam can be set up as a service but doesn't record video. IspyConnect has exactly the type of space limit I want and looks great, but doesn't run as a service (seems also to be a bit of a cpu hog) Any other suggestions? I'm locked into Windows so can't use linux Motion, which looks almost perfect. Any pointers to rich Windows webcam/motion detection libraries out there that could easily be turned into a command line program would also be appreciated.

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  • Linux security: The dangers of executing malignant code as a standard user

    - by AndreasT
    Slipping some (non-root) user a piece of malignant code that he or she executes might be considered as one of the highest security breaches possible. (The only higher I can see is actually accessing the root user) What can an attacker effectively do when he/she gets a standard, (let's say a normal Ubuntu user) to execute code? Where would an attacker go from there? What would that piece of code do? Let's say that the user is not stupid enough to be lured into entering the root/sudo password into a form/program she doesn't know. Only software from trusted sources is installed. The way I see it there is not really much one could do, is there? Addition: I partially ask this because I am thinking of granting some people shell (non-root) access to my server. They should be able to have normal access to programs. I want them to be able to compile programs with gcc. So there will definitely be arbitrary code run in user-space...

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  • Log4j: Events appear in the wrong logfile

    - by Markus
    Hi there! To be able to log and trace some events I've added a LoggingHandler class to my java project. Inside this class I'm using two different log4j logger instances - one for logging an event and one for tracing an event into different files. The initialization block of the class looks like this: public void initialize() { System.out.print("starting logging server ..."); // create logger instances logLogger = Logger.getLogger("log"); traceLogger = Logger.getLogger("trace"); // create pattern layout String conversionPattern = "%c{2} %d{ABSOLUTE} %r %p %m%n"; try { patternLayout = new PatternLayout(); patternLayout.setConversionPattern(conversionPattern); } catch (Exception e) { System.out.println("error: could not create logger layout pattern"); System.out.println(e); System.exit(1); } // add pattern to file appender try { logFileAppender = new FileAppender(patternLayout, logFilename, false); traceFileAppender = new FileAppender(patternLayout, traceFilename, false); } catch (IOException e) { System.out.println("error: could not add logger layout pattern to corresponding appender"); System.out.println(e); System.exit(1); } // add appenders to loggers logLogger.addAppender(logFileAppender); traceLogger.addAppender(traceFileAppender); // set logger level logLogger.setLevel(Level.INFO); traceLogger.setLevel(Level.INFO); // start logging server loggingServer = new LoggingServer(logLogger, traceLogger, serverPort, this); loggingServer.start(); System.out.println(" done"); } To make sure that only only thread is using the functionality of a logger instance at the same time each logging / tracing method calls the logging method .info() inside a synchronized-block. One example looks like this: public void logMessage(String message) { synchronized (logLogger) { if (logLogger.isInfoEnabled() && logFileAppender != null) { logLogger.info(instanceName + ": " + message); } } } If I look at the log files, I see that sometimes a event appears in the wrong file. One example: trace 10:41:30,773 11080 INFO masterControl(192.168.2.21): string broadcast message was pushed from 1267093 to vehicle 1055293 (slaveControl 1) trace 10:41:30,784 11091 INFO masterControl(192.168.2.21): string broadcast message was pushed from 1156513 to vehicle 1105792 (slaveControl 1) trace 10:41:30,796 11103 INFO masterControl(192.168.2.21): string broadcast message was pushed from 1104306 to vehicle 1055293 (slaveControl 1) trace 10:41:30,808 11115 INFO masterControl(192.168.2.21): vehicle 1327879 was pushed to slave control 1 10:41:30,808 11115 INFO masterControl(192.168.2.21): string broadcast message was pushed from 1101572 to vehicle 106741 (slaveControl 1) trace 10:41:30,820 11127 INFO masterControl(192.168.2.21): string broadcast message was pushed from 1055293 to vehicle 1104306 (slaveControl 1) I think that the problem occures everytime two event happen at the same time (here: 10:41:30,808). Does anybody has an idea how to solve my problem? I already tried to add a sleep() after the method call, but that doesn't helped ... BR, Markus Edit: logtrace 11:16:07,75511:16:07,755 1129711297 INFOINFO masterControl(192.168.2.21): string broadcast message was pushed from 1291400 to vehicle 1138272 (slaveControl 1)masterControl(192.168.2.21): vehicle 1333770 was added to slave control 1 or log 11:16:08,562 12104 INFO 11:16:08,562 masterControl(192.168.2.21): string broadcast message was pushed from 117772 to vehicle 1217744 (slaveControl 1) 12104 INFO masterControl(192.168.2.21): vehicle 1169775 was pushed to slave control 1 Edit 2: It seems like the problem only occurs if logging methods are called from inside a RMI thread (my client / server exchange information using RMI connections). ... Edit 3: I solved the problem by myself: It seems like log4j is NOT completely thread-save. After synchronizing all log / trace methods using a separate object everything is working fine. Maybe the lib is writing the messages to a thread-unsafe buffer before writing them to file?

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  • Security failure - This is not a secure document but has security embed parameters

    - by dimitris mistriotis
    I try to create a private version and therefore I used something like this in php: var scribd_doc = scribd.Document.getDoc( 28394353, 'xxx'); scribd_doc.addParam("use_ssl", true); scribd_doc.addParam('public', false); scribd_doc.grantAccess("cbccf6e7-1ff7-9034-8a7c-a0c2a5b225ed", <?php echo "'" . trim($_COOKIE['PHPSESSID']) . "'" ?>, <?php echo "'" . scribd_calculate_signature($documentID = '28394353', $sessionID = trim($_COOKIE['PHPSESSID']), $userID = "cbccf6e7-1ff7-9034-8a7c-a0c2a5b225ed") . "'" ?>); ... ... scribd_doc.write( 'embedded_flash' ); Which is the api of scribd for javascript with the addition of the signature. My result is the "Security failure - This is not a secure document but has security embed parameters" Error, which is not well documented. The document is set to private. Any ideas?

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  • C#/.NET Little Wonders: The EventHandler and EventHandler&lt;TEventArgs&gt; delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last two weeks, we examined the Action family of delegates (and delegates in general), and the Func family of delegates and how they can be used to support generic, reusable algorithms and classes. So this week, we are going to look at a handy pair of delegates that can be used to eliminate the need for defining custom delegates when creating events: the EventHandler and EventHandler<TEventArgs> delegates. Events and delegates Before we begin, let’s quickly consider events in .NET.  According to the MSDN: An event in C# is a way for a class to provide notifications to clients of that class when some interesting thing happens to an object. So, basically, you can create an event in a type so that users of that type can subscribe to notifications of things of interest.  How is this different than some of the delegate programming that we talked about in the last two weeks?  Well, you can think of an event as a special access modifier on a delegate.  Some differences between the two are: Events are a special access case of delegates They behave much like delegates instances inside the type they are declared in, but outside of that type they can only be (un)subscribed to. Events can specify add/remove behavior explicitly If you want to do additional work when someone subscribes or unsubscribes to an event, you can specify the add and remove actions explicitly. Events have access modifiers, but these only specify the access level of those who can (un)subscribe A public event, for example, means anyone can (un)subscribe, but it does not mean that anyone can raise (invoke) the event directly.  Events can only be raised by the type that contains them In contrast, if a delegate is visible, it can be invoked outside of the object (not even in a sub-class!). Events tend to be for notifications only, and should be treated as optional Semantically speaking, events typically don’t perform work on the the class directly, but tend to just notify subscribers when something of note occurs. My basic rule-of-thumb is that if you are just wanting to notify any listeners (who may or may not care) that something has happened, use an event.  However, if you want the caller to provide some function to perform to direct the class about how it should perform work, make it a delegate. Declaring events using custom delegates To declare an event in a type, we simply use the event keyword and specify its delegate type.  For example, let’s say you wanted to create a new TimeOfDayTimer that triggers at a given time of the day (as opposed to on an interval).  We could write something like this: 1: public delegate void TimeOfDayHandler(object source, ElapsedEventArgs e); 2:  3: // A timer that will fire at time of day each day. 4: public class TimeOfDayTimer : IDisposable 5: { 6: // Event that is triggered at time of day. 7: public event TimeOfDayHandler Elapsed; 8:  9: // ... 10: } The first thing to note is that the event is a delegate type, which tells us what types of methods may subscribe to it.  The second thing to note is the signature of the event handler delegate, according to the MSDN: The standard signature of an event handler delegate defines a method that does not return a value, whose first parameter is of type Object and refers to the instance that raises the event, and whose second parameter is derived from type EventArgs and holds the event data. If the event does not generate event data, the second parameter is simply an instance of EventArgs. Otherwise, the second parameter is a custom type derived from EventArgs and supplies any fields or properties needed to hold the event data. So, in a nutshell, the event handler delegates should return void and take two parameters: An object reference to the object that raised the event. An EventArgs (or a subclass of EventArgs) reference to event specific information. Even if your event has no additional information to provide, you are still expected to provide an EventArgs instance.  In this case, feel free to pass the EventArgs.Empty singleton instead of creating new instances of EventArgs (to avoid generating unneeded memory garbage). The EventHandler delegate Because many events have no additional information to pass, and thus do not require custom EventArgs, the signature of the delegates for subscribing to these events is typically: 1: // always takes an object and an EventArgs reference 2: public delegate void EventHandler(object sender, EventArgs e) It would be insane to recreate this delegate for every class that had a basic event with no additional event data, so there already exists a delegate for you called EventHandler that has this very definition!  Feel free to use it to define any events which supply no additional event information: 1: public class Cache 2: { 3: // event that is raised whenever the cache performs a cleanup 4: public event EventHandler OnCleanup; 5:  6: // ... 7: } This will handle any event with the standard EventArgs (no additional information).  But what of events that do need to supply additional information?  Does that mean we’re out of luck for subclasses of EventArgs?  That’s where the generic for of EventHandler comes into play… The generic EventHandler<TEventArgs> delegate Starting with the introduction of generics in .NET 2.0, we have a generic delegate called EventHandler<TEventArgs>.  Its signature is as follows: 1: public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e) 2: where TEventArgs : EventArgs This is similar to EventHandler except it has been made generic to support the more general case.  Thus, it will work for any delegate where the first argument is an object (the sender) and the second argument is a class derived from EventArgs (the event data). For example, let’s say we wanted to create a message receiver, and we wanted it to have a few events such as OnConnected that will tell us when a connection is established (probably with no additional information) and OnMessageReceived that will tell us when a new message arrives (probably with a string for the new message text). So for OnMessageReceived, our MessageReceivedEventArgs might look like this: 1: public sealed class MessageReceivedEventArgs : EventArgs 2: { 3: public string Message { get; set; } 4: } And since OnConnected needs no event argument type defined, our class might look something like this: 1: public class MessageReceiver 2: { 3: // event that is called when the receiver connects with sender 4: public event EventHandler OnConnected; 5:  6: // event that is called when a new message is received. 7: public event EventHandler<MessageReceivedEventArgs> OnMessageReceived; 8:  9: // ... 10: } Notice, nowhere did we have to define a delegate to fit our event definition, the EventHandler and generic EventHandler<TEventArgs> delegates fit almost anything we’d need to do with events. Sidebar: Thread-safety and raising an event When the time comes to raise an event, we should always check to make sure there are subscribers, and then only raise the event if anyone is subscribed.  This is important because if no one is subscribed to the event, then the instance will be null and we will get a NullReferenceException if we attempt to raise the event. 1: // This protects against NullReferenceException... or does it? 2: if (OnMessageReceived != null) 3: { 4: OnMessageReceived(this, new MessageReceivedEventArgs(aMessage)); 5: } The above code seems to handle the null reference if no one is subscribed, but there’s a problem if this is being used in multi-threaded environments.  For example, assume we have thread A which is about to raise the event, and it checks and clears the null check and is about to raise the event.  However, before it can do that thread B unsubscribes to the event, which sets the delegate to null.  Now, when thread A attempts to raise the event, this causes the NullReferenceException that we were hoping to avoid! To counter this, the simplest best-practice method is to copy the event (just a multicast delegate) to a temporary local variable just before we raise it.  Since we are inside the class where this event is being raised, we can copy it to a local variable like this, and it will protect us from multi-threading since multicast delegates are immutable and assignments are atomic: 1: // always make copy of the event multi-cast delegate before checking 2: // for null to avoid race-condition between the null-check and raising it. 3: var handler = OnMessageReceived; 4: 5: if (handler != null) 6: { 7: handler(this, new MessageReceivedEventArgs(aMessage)); 8: } The very slight trade-off is that it’s possible a class may get an event after it unsubscribes in a multi-threaded environment, but this is a small risk and classes should be prepared for this possibility anyway.  For a more detailed discussion on this, check out this excellent Eric Lippert blog post on Events and Races. Summary Generic delegates give us a lot of power to make generic algorithms and classes, and the EventHandler delegate family gives us the flexibility to create events easily, without needing to redefine delegates over and over.  Use them whenever you need to define events with or without specialized EventArgs.   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Delegates, EventHandler

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  • jQuery problem with change event and IE8

    - by Marcus
    There is a bug in jQuery 1.4.2 that makes change event on select-element getting fired twice when using both DOM-event and a jQuery event, and this only on IE7/8. Here is the test code: <html> <head> <script src="http://code.jquery.com/jquery-1.4.2.js" type="text/javascript"></script> <script type="text/javascript"> jQuery(document).ready(function() { jQuery(".myDropDown").change(function() { }); }); </script> </head> <body> <select class="myDropDown" onchange="alert('hello');"> <option>1</option> <option>2</option> <option>3</option> <option>4</option> </select> </body> </html> Ticket to actual bug: http://dev.jquery.com/ticket/6593 This causes alot of trouble for us in our application cause we use both ASP.NET-events mixed with jQuery and once you hook up a change event on any element every select (dropdown) gets this double firing problem. Is there anyone who knows a way around this in the meantime until this issue is fixed?

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  • Problems with registering click event listener to a frame-element

    - by distractedBySquirrels
    Hi everybody, I ran into a problem with adding an event listener. I wrote a Firefox plugin a while ago for my bachelor thesis. It was based on a different attacker model than you would normally expect. In this scenario the attacker was the service provider (like Facebook, Google,...), who reads all your private data stored on their site (via JS). My final solution was to temporally allow JS (while the page loads and after an user action occured). To observe the interaction I used event listener, which worked very well so far. But last week I noticed that my approach doesn't work with web sites which are using a frameset (I added the event listener to the body...). So I tried to add the listener to the frameset respectively to the frame. But the clicks are only noticed when you actually click on the frame... (eg resize the frame with your mouse) But I want to register clicks on the document loaded inside the frame. I already tried the .frameElement. Sadly it seems that Firefox doesn't like my (or, which is more likely, I'm too stuipd :) ) and claims there are no frames... Could anyone tell me how to add an event listener to the document inside a frame? The web site looks like this: <html> <head> <title>Frameset Test</title> </head> <frameset cols="150,*"> <frame src="nav.html" name="Navigation"> <frame src="main.html" name="Main"> </frameset> </html> This was my first bigger projekt with Mozilla so this could be a really dumb failure of mine... I hope you guys can help me. Thanks in advance. Sebastian

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  • How can you become a competent web application security expert without breaking the law?

    - by hal10001
    I find this to be equivalent to undercover police officers who join a gang, do drugs and break the law as a last resort in order to enforce it. To be a competent security expert, I feel hacking has to be a constant hands-on effort. Yet, that requires finding exploits, testing them on live applications, and being able to demonstrate those exploits with confidence. For those that consider themselves "experts" in Web application security, what did you do to learn the art without actually breaking the law? Or, is this the gray area that nobody likes to talk about because you have to bend the law to its limits?

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  • How do I get security updates for restricted/partner packages?

    - by laramichaels
    I want to perform just security updates on Ubuntu 12.04 LTS, keeping the rest of the system unchanged. I need to do this from the command line, no the GUI update manager. I have implemented the solution described here, which seems to work great for this purpose. I merely substituted 'precise' for 'lucid' given that I am on 12.04. My question is: by using apt pinning as described in that answer, will I still receive security updates for packages distributed through the "other" repositories - partner, restricted, multiverse, etc? Or will it only get me updates for the packages in the "core" distribution? thanks! ~l

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  • flash as3 document class and event listeners

    - by Lee
    I think i have this document class concept entirly wrong now, i was wondering if someone mind explaining it.. I assumed that the above class would be instantiated within the first frame on scene one of a movie. I also assumed that when changing scenes the state of the class would remain constant so any event listeners would still be running.. Scene 1: I have a movieclip named ui_mc, that has a button in for muting sound. Scene 2: I have the same movie clip with the same button. Now the eventListener picks it up in the first scene, however it does not in the second. I am wondering for every scene do the event listeners need to be resetup? If that is the case if their an event listener to listen for the change in scene, so i can set them back up again lol.. Thanks in advance.. package { import flash.display.MovieClip; import flash.events.MouseEvent; import flash.media.Sound; import flash.media.SoundChannel; public class game extends MovieClip { public var snd_state:Boolean = true; public function game() { ui_setup(); } public function ui_setup():void { ui_mc.toggleMute_mc.addEventListener(MouseEvent.CLICK, snd_toggle); } private function snd_toggle(event:MouseEvent):void { // 0 = No Sound, 1 = Full Sound trace("Toggle"); } } }

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  • Are all "Important security updates", updates to already installed packages?

    - by Omnicomment
    I'm running 12.04, and I've never downloaded any drivers for the installation of any peripheral devices. Yet, I noticed a fair few "Important security updates" involving drivers/utilities for HP devices/software. I understand if the default installation of Ubuntu came with a set of drivers for these devices - and the update manager, having noticed that they live on my system, went and found newer versions, but still - given I don't use any devices - I'm either forced to download an irrelevant update, sift through the updates to check applicability, or turn off Update Manager altogether: none of which are desirable. First; the obvious - can someone confirm that the list of "Important security updates" on the server that Update manager connects to, is not actually populated with every patch ever written (i.e. for all Ubuntu packages regardless of whether they're installed or not)? Unlikely, but..

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  • How to learn what the industry standards/expectations are, particularly with security?

    - by Aerovistae
    For instance, I was making my first mobile web-application about a year ago, and half-way through, someone pointed me to jQuery Mobile. Obviously this induced a total revolution in my app. Rewrote everything. Now, if you're in the field long enough, maybe that seems like common knowledge, but I was totally new to it. But this set me wondering: there are so many libraries and extensions and frameworks. This seems particularly crucial in the category of security. I'm afraid I'm going to find myself doing something in a professional setting eventually (I'm still a student) and someone's going to walk over and be like, My god, you're trying to secure user data that way? Don't you know about the Gordon-Wokker crypto-magic-hash-algorithms library? Without it you may as well go plaintext. How do you know what the best ways are to maximize security? Especially if you're trying to develop something on your own...

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  • Are there commercially deployed and used .NET CAS (Code Access Security) based applications?

    - by Dinis Cruz
    I've seen a couple threads here on SO that ask about what CAS is and how to use it.My specific is specifically focused on real-world usages of CAS. For example: DotNetNuke did some efforts in the past to be able to run under Medium Trust: is that still true? what is the % of DNN that run in partial trust (i.e. not full trust)? what & of DNN modules run in partial trust?) Sharepoint defaults to a Partially-Trusted environment on dlls executed from the bin folder: How many 'commercially' available WebParts can run in this bin folder (without changing the policy)? The key here is to be able to point to CAS success stories, so that other companies feel that they should also invest in writing CAS-enabled apps

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