"A really bad week." That's what the @RISK editor and Tippingpoint vulnerability researcher, Rohit Dhamankar wrote to us this morning. And the director of the Internet Storm Center, Johannes Ullrich readily agreed. Why?
Two zero-day vulnerabilities. Active exploits. No effective defenses. Windows had a zero-day that affects Vista as well as older versions. So important that Microsoft is issuing a special patch tomorrow and leaked it to a few folks today. The other zero-day hit CA's BrightStor. Holes in backup software may be more damaging than holes in operating systems because the vendors of backup software don't have the same level of automating patching that the operating system vendors have, and many users have *never* patched their backup software. And Lotus Domino users also had multiple vulnerabilities, some critical. Alan
PS. The good folks at SPI Dynamics contributed a useful status report on the first half of the "Month of PHP Bugs (MOPB)." It is at the end of this issue.
PPS. If you have any interest in application security join us for the webcast on the new examination and new developments in application security tools (Wednesday noon EDT) https://www.sans.org/webcasts/show.php?webcastid=91206
@RISK is the SANS community's consensus bulletin summarizing the most important vulnerabilities and exploits identified during the past week and providing guidance on appropriate actions to protect your systems (PART I). It also includes a comprehensive list of all new vulnerabilities discovered in the past week (PART II).
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Part I for this issue has been compiled by Rob King and Rohit Dhamankar at TippingPoint, a division of 3Com, as a by-product of that company's continuous effort to ensure that its intrusion prevention products effectively block exploits using known vulnerabilities. TippingPoint's analysis is complemented by input from a council of security managers from twelve large organizations who confidentially share with SANS the specific actions they have taken to protect their systems. A detailed description of the process may be found at http://www.sans.org/newsletters/cva/#process
Description: Microsoft Windows contains a buffer overflow vulnerability that can be triggered by specially crafted "animated cursor" files. The animated cursor files (".ani" file extension) are used to store animated cursors and icon graphics. A malicious ANI file could exploit the buffer overflow to execute arbitrary code with the privileges of the current user. To exploit the flaw, an attacker can take any of the following actions: (a) Create a webpage containing a malicious .ani file and entice an attacker to visit his webpage. (b) Send an HTML email containing the malicious .ani file. (c) Create a shared folder containing the malicious .ani file and entice a user to browse his shared folder. This flaw is being exploited in the wild by a number of malicious websites. Please note that the overflow can be exploited by spoofing the file extension for other image formats such as JPEG. Windows will invoke the vulnerable component upon inspecting the file header.
Status: Microsoft confirmed. Due to widespread exploitation, Microsoft is planning to release an emergency patch tomorrow. SANS Internet Storm Center maintains a list of domains that are distributing the exploit code. Please block any access to the domains listed here: http://isc.sans.org/diary.html?storyid=2540
Council Site Actions: All of the reporting council sites are waiting for the Microsoft patch.
Description: Computer Associates BrightStor ARCserve Backup products provide backup services for Microsoft Windows, Novell NetWare, Linux, and UNIX. The "mediasrvr.exe" process contains a buffer overflow vulnerability in the handling of RPC requests. A specially-crafted request to procedure 191 could trigger this buffer overflow. Successfully exploiting this buffer overflow would allow an attacker to execute arbitrary code with the privileges of the "mediaserv.exe" process, usually "SYSTEM/root". Note that a working exploit is publicly available for this vulnerability.
Status: Computer Associates confirmed, no updates available. Users may be able to mitigate the impact of this vulnerability by renaming the "mediasvr.exe" file to another name (e.g. "mediasvr.disabled") and restarting the BrightStor Tape Engine service.
Description: IBM Lotus Domino, a popular enterprise groupware and mail system, contains multiple vulnerabilities: (a) A specially-crafted CRAM-MD5 login request could trigger a buffer overflow in the IMAP server process by sending an overlong (greater than 256 bytes) username. Successfully exploiting this vulnerability would allow an attacker to execute arbitrary code with the privileges of the IMAP server process, usually SYSTEM/root. Exploit code has been publicly posted. (b) A specially-crafted Distinguished Name (DN) in an LDAP message with an overlong string (longer than 65535 bytes) could trigger a heap-based buffer overflow. Successfully exploiting this vulnerability would allow an attacker to execute arbitrary code with the privileges of the LDAP server process, usually SYSTEM/root. (c) The Web Access component of Domino fails to properly sanitize some specially-crafted email messages. A specially-crafted message could bypass this filtering and allow arbitrary scripts to be executed in a user's browser in the same security context as pages served by the Domino server.
Status: IBM confirmed, updates available.
Council Site Actions: The affected software and/or configuration are not in production or widespread use, or are not officially supported at any of the council sites. They reported that no action was necessary.
Description: The "SuperBuddy" ActiveX control, shipped by default with recent versions of the America Online (AOL) software, contains a vulnerability in the handling of certain parameters passed to its "LinkSBIcons" method. A specially-crafted web page that instantiates this control could exploit this vulnerability to execute arbitrary code with the privileges of the current user. Note that some technical details are publicly available for this vulnerability, and that reusable exploit code that targets arbitrary ActiveX controls is widely available and easily adaptable to this vulnerability. This software is shipped by default by several PC vendors, including Dell and HP.
Status: AOL confirmed, updates available. Note that the update is currently believed to be available only to users of AOL's internet service; users of other services may not have access to the update. Users can mitigate the impact of this vulnerability by disabling the control via Microsoft's "kill bit" mechanism for CLSID "189504B8-50D1-4AA8-B4D6-95C8F58A6414".
Description: Corel WordPerfect Office, a popular office suite, contains a buffer overflow vulnerability. A specially-crafted document containing an overlong printer selection name could trigger this buffer overflow and execute arbitrary code with the privileges of the current user. Depending upon configuration, these documents may be opened without prompting. Note that a working exploit for this vulnerability is publicly available.
Status: Corel has not confirmed, no updates available.
Council Site Actions: The affected software and/or configuration are not in production or widespread use, or are not officially supported at any of the council sites. They reported that no action was necessary.
Description: Cisco Unified CallManager, Cisco's Voice-over-IP (VoIP) call processing system, contains multiple denial-of-service vulnerabilities: (a) Failure to properly process certain Skinny Call Control Protocol (SCCP) requests could trigger a denial-of-service condition affecting voice services. SCCP operations on TCP ports 2000 and 2443. (b) Failure to properly handle large amounts of ICMP Echo Requests (commonly referred to as "pings") could trigger several denial-of-service conditions, affecting voice services. (c) A specially-crafted UDP packet sent to the IPSec Manager Server on UDP port 8500 could trigger a denial-of-service condition affecting call forwarding and deployment of configuration changes.
Status: Cisco confirmed, updates available.
Council Site Actions: Two of the reporting council sites are using the affected software. One site plans to deploy the updates during their next regular maintenance cycle. The other site is working out their plan for patching.
Description: The SignKorea SKCommAX ActiveX control, designed to perform certificate and identity validation, contains a buffer overflow vulnerability. By passing an overly-long "UserID" parameter to the "DownloadCertificateExt" method in this control, a malicious web page could exploit this buffer overflow and execute arbitrary code with the privileges of the current user. Note that reusable exploit code that targets ActiveX controls is widely available and can be easily adapted to exploit this control.
Status: SignKorea confirmed, updates available.
Council Site Actions: The affected software and/or configuration are not in production or widespread use, or are not officially supported at any of the council sites. They reported that no action was necessary. One site commented that any attempt to download this component would be blocked by their active content filter and any attempt to exploit the vulnerability would be blocked by their web-proxy anti-malaria.
Description: InterVetions NaviCopa, a popular HTTP server for Microsoft Windows, contains a buffer overflow vulnerability. By passing an overlong URL to the server, an attacker could overflow a stack-based buffer and execute arbitrary code with the privileges of the server process. A working exploit and full technical details are available for this vulnerability.
Status: InterVetions confirmed, updates available.
Council Site Actions: The affected software and/or configuration are not in production or widespread use, or are not officially supported at any of the council sites. They reported that no action was necessary.
This list is compiled by Qualys ( www.qualys.com ) as part of that company's ongoing effort to ensure its vulnerability management web service tests for all known vulnerabilities that can be scanned. As of this week Qualys scans for 5411 unique vulnerabilities. For this special SANS community listing, Qualys also includes vulnerabilities that cannot be scanned remotely.
(c) 2007. All rights reserved. The information contained in this newsletter, including any external links, is provided "AS IS," with no express or implied warranty, for informational purposes only. In some cases, copyright for material in this newsletter may be held by a party other than Qualys (as indicated herein) and permission to use such material must be requested from the copyright owner.
THE MONTH OF PHP BUGS
The month of March brought us the Month of PHP Bugs (MOPB), a full-disclosure campaign aimed at improving the overall security in the popular PHP application server platform. Like previous Month of Bugs initiatives (Month of Brower Bugs, Month of Apple Bugs), the MOPB coordinators are releasing a new bug every day for the entire month of March. One of the heavy-hitters behind MOPB is Stefan Esser, a former member of the PHP security response team. Stefan left the PHP security team due to a lack of momentum and various impasses in fixing the security bugs he found.
Politics aside, the MOPB effort has lived up to its promise. We've seen a new bug every day. But should PHP users be worried? At the middle of the month, we performed a 'mid-month' analysis of the bugs released so far. The analysis reviewed the overall impact of the bugs, their applicability to common deployments, and how they were being fixed by the PHP developers. The mid-month analysis is available at: http://portal.spidynamics.com/blogs/jeff/archive/2007/03/19/Month-of-PHP-Bugs_3A
00_-Mid_2D00_month-analysis.aspx
The biggest conclusion of the mid-month analysis was that typical users of the latest versions of PHP (5.2.1 and 4.4.5) only needed to worry about two bugs (MOPB #1 and #2). Those two bugs allow a remote attacker to perform a denial of service attack on the server. The remaining bugs were either fixed in the last released version of PHP, or require a local user/malicious PHP script executed on the system to exploit the bug. We also reviewed the bugs released after the mid-month analysis; our general conclusion is that the analysis results/conclusions are unaffected, as the newer bugs didn't change the overall dynamics of what was already released.
This brings up two important points: if you're not running the latest version of PHP (specifically 5.2.1 and 4.4.5), you should strongly investigate upgrading immediately. Many of the MOPB releases highlight bugs fixed in those releases, and some of them can be considered quite serious. Also, if you happen to be a web hosting provider or otherwise allow arbitrary users to upload and execute PHP scripts, you are in a very serious predicament: most of the MOPB bugs require local access to exploit, and once exploited, allow the arbitrary execution of code which can circumvent PHP's built-in safemode and other security restrictions. You may consider looking to Esser et. al.'s excellent and free Hardened-PHP or Suhosin patches to proactively add additional security constraints to PHP (and help mitigate many of the MOPB bugs in the process).
So far the PHP security team/developers have been making moderate fixes in response to the MOPB bugs. However, two things get called into question. First, just because the PHP team has committed a patch, doesn't mean the bug is fixed. We've witnessed a few occasions were the fix wasn't thorough enough or improperly applied. One of the MOPB bugs (#32) actually points to a new security problem introduced by the ad-hoc fix of MOPB bug #31. So while the speed of the PHP developers in committing patches is high, we can't necessarily say the same of the quality and thoroughness of the fixes. Second, even if all the fixes are committed to the development source code repository (CVS), we still have to wait for when the PHP team rolls the latest code into an official release. People generally don't deploy beta CVS snapshots of software on their production systems-so those fixes won't see widespread deployment an official release is tested and made. And right now, there's no telling when that will happen. We hope it will occur almost immediately after the MOPB ends, but ultimately we will have to wait and see.
Even when there is an official PHP release, there can still be additional delay for various OS/package distributors (i.e. Linux, BSD) to turn the PHP release into a distribution package. For example, if you're a SuSE user, and you are using the SuSE RPM version of PHP, then after the PHP team releases the next version (i.e. 5.2.2 and/or 4.4.6), you still have to wait until SuSE either makes a new PHP RPM or back-ports the fixes to whatever PHP version branch they are using.
Curiosity got the better of us, so we decided to look at the various development mailing lists of many popular OS distributions (OpenBSD, FreeBSD, SuSE, Debian, and Fedora). We searched CVS commit lists, development discussion lists, and ports commit lists for any reference to PHP made on or after March 1st. We found OpenSuSE was the only one to have committed fixes for the MOPB bugs to their distribution package repository. SuSE also made a public statement in their latest Security Summary Report indicating they are watching the progress of the MOPB campaign and plan to act after it concludes. But aside from those two cases, our cursory look into the development efforts of some popular OS distros didn't turn up any current efforts to dealing with any of the problems uncovered by the MOPB effort. We do want to explicitly note that this isn't necessarily a bad thing-it is understandable to wait until the conclusion of the MOPB campaign before acting. Plus, this doesn't reflect any private development efforts that haven't been committed into CVS yet. Regardless, it's still an interesting observation.
Overall this is an interesting time for PHP users. While there will be a little bit of turmoil in the release and deployment of the next PHP version, overall Esser and the MOPB crew have successfully bolstered the security of PHP. Combined with their ongoing efforts on the free Hardened-PHP and Suhosin security enhancements for PHP, I think one thing is clear: Esser and the MOPB crew truly are just trying to make the world a more secure place for PHP users. And for that, we should thank them.
Resources: Month of PHP Bugs: http://www.php-security.org/
Month of PHP Bugs: Mid-month analysis http://portal.spidynamics.com/blogs/jeff/archive/2007/03/19/Month-of-PHP-Bugs_3A
00_-Mid_2D00_month-analysis.aspx
Hardened-PHP project: http://www.hardened-php.net/
Suhosin PHP security extension: http://www.hardened-php.net/ suhosin/index.html
Questions: http://portal.spidynamics.com/blogs/spilabs/default.aspx
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