A light week for critical new vulnerabilities in operating systems and major applications offers us all an opportunity to focus on vulnerable web applications. Few targets are more inviting or more vulnerable than web applications written by people who are not super savvy about avoiding SQL injection and "remote file include" vulnerabilities. If you don't have a systematic way of eliminating these common errors, your systems and your customers' private information are easy pickings. (SANS Track 4: Hacker Exploits, at SANS Security San Diego and SANSFIRE in Washington, and in eleven other cities around the world and live on line is a great way to make sure you know how the attacks work and what to do about them: http://www.sans.org )
Alan
@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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Note: The number of SQL injection and remote file include vulnerabilities continues to increase, and many of these vulnerabilities are being actively exploited. The vulnerabilities are listed in separate sub-sections in Part 2 of the newsletter, and we avoid repeating them in Part 1. For this week, users of Claroline, PHP-Nuke-Clan, and PHPMyChat should harden their installations as exploits for the flaws in these packages are publicly available. The SANS Top-20 is another good reference to harden against PHP-based attacks - http://www.sans.org/top20/#c3
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Part I is compiled by 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: ClamAV is an open-source antivirus software designed mainly for scanning emails on UNIX mail gateways. The software includes a virus scanning library - libClamAV. This library is used by many third party email, web, FTP scanners as well as mail clients. The library contains an integer overflow that can be triggered by a specially crafted Windows Executable (PE format) if the "ArchiveMaxFileSize" option is disabled (not a default configuration). The attacker can send the malicious files via email, web, FTP or a file share, and exploit the overflow to execute arbitrary code on the system running the ClamAV library. Proof-of-concept Windows executable has been posted. The library also contains a format string vulnerability in its logging function for which limited technical details are available.
Status: Vendor confirmed, upgrade to ClamAV version 0.88.1.
Council Site Actions: Only one council site was affected by this issue. They have a few installations of this software, primarily on Debian GNU/Linux systems that are relied upon by relatively small numbers of users. Those systems will obtain the DSA-1024-1 update, or already have done so.
Description: This vulnerability in Internet Explorer can be exploited to spoof the address bar displayed by Internet Explorer i.e. the address bar can be made to point to a different webpage while the content is loaded from the attacker's webpage. The vulnerability arises due to timing issues in Internet Explorer when it tries to load a macromedia flash file and another webpage in the same browser window in a quick succession. An attacker can exploit this flaw to conduct phishing attacks, which continue to be on a rise. Exploit code is publicly available.
Status: Microsoft not confirmed, no patches available. A workaround is to disable "Active Scripting". Note that disabling Active Scripting will also help in protecting from certain 0-day vulnerabilities in Internet Explorer.
Description: Barracuda Spam Firewall appliance is designed to protect e-mail servers from viruses, spam, spyware etc. The mail filtering software contains stack-based buffer overflows that can be triggered by specially crafted e-mail attachments. Specifically ZOO and LHA archives with overlong filenames in the archive trigger these overflows that can be exploited to execute arbitrary code on the appliance. Pirana, a tool to test e-mail content filtering solutions, can be used to exploit these overflows. The posted advisory shows how to use the Pirana tool to get a remote shell access to the appliance.
Status: Barracuda released a critical spamdef patch version 3.0.9388 on March 3, 2006 to mitigate the issue. It is advised to upgrade to firmware version 3.3.03.022.
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: McAfee WebShield SMTP is a Windows-based software that scans e-mails for malicious attachments. This software contains a format string vulnerability that can be triggered when the software processes an email addressed to a non-existent domain. An unauthenticated attacker can exploit this flaw by sending an email to a non-existent domain with the email address containing format specifiers (such as %s), and execute arbitrary code on the WebShield server with SYSTEM privileges.
Status: McAfee released patch P0803 for version 4.5MR1a three years back. Version 4.5MR2 contains a fix for this issue.
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: Ultr@VNC is an open-source VNC viewer that allows remote access to Windows-based systems. The VNC server contains a buffer overflow in its logging function that can be triggered by sending an overlong HTTP request (over 1024 bytes) to port 5800/tcp. If the "Log debug infos to the WinVNC.log file" option is enabled on the VNC server, the flaw can be exploited to execute arbitrary code. The client also contains a buffer overflow that can be triggered by a server response greater than 1024 bytes. The client overflow is difficult to exploit as the user needs to be tricked into connecting to a malicious VNC server. Proof-of-concept exploits for both flaws have been publicly posted.
Status: Vendor not confirmed, no patch available. Block HTTP requests over 1024 bytes to port 5800/tcp if running a UltraVNC server.
Council Site Actions: Only one of the reporting council sites is using the affected software. They have only a few installations. In addition, they feel that the conditions for exploitation would be difficult to achieve given the details of the deployment, and have classified this as a low risk.
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 4964 unique vulnerabilities. For this special SANS community listing, Qualys also includes vulnerabilities that cannot be scanned remotely.
(c) 2006. 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.
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