@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 is compiled by the security team at TippingPoint (www.tippingpoint.com) 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: AOL Instant Messenger (AIM) installs a URI handler on the Windows system. Hence, the instant messenger application can be invoked via a web browser with a URI beginning with "aim:". The "goaway" function of the AIM URI handler contains a stack-based buffer overflow. The flaw can be triggered by an URL of the form "aim:goaway?message=<overlong message over 980 bytes>". A malicious webpage, an HTML email or an AIM peer can exploit this flaw to execute arbitrary code on a client system with the privileges of the logged-on user. Exploit code has been publicly posted.
Status: AOL has confirmed the flaw, and a beta update is available. Note that the suggested fix of removing the AIM URI handler by deleting the "HKEY_CLASSES_ROOT\aim" registry key does not offer a permanent protection. This workaround fails because as soon as AIM is launched again, the registry key is re-created. A registry change that will disable the "aim" protocol permanently has been posted at http://www.pivx.com/research/freefixes/neuteraimurl.reg Council Site Actions: Only a few council sites are using the affected software in an officially supported fashion. These sites are waiting on a non-beta version of the patch before deploying. Most of the council sites do not support the affected software. Although they may have users who use this application, they do not plan any actions at this time.
Description: Adobe Acrobat Reader, the popularly used PDF viewer, reportedly contains multiple vulnerabilities in its "uudecoding" feature. The uuencode function converts binary data to ASCII printable characters. For instance, this function is typically used to convert binary e-mail attachments to the text format. The uudecode function converts the uuencoded data back to the original binary. Adobe Acrobat Reader automatically attempts to decode a uuencoded PDF file. The decoding function contains the following vulnerabilities: (a) The Adobe Acrobat Reader contains a buffer overflow that can be triggered by an overlong file name. (b) The Adobe Acrobat Reader contains a remote command injection vulnerability that can be triggered by a specially crafted filename i.e. a filename containing shell metacharacters. A malicious webpage or an email attachment may exploit these flaws to execute arbitrary code on a client system with the privileges of the logged-on user.
Status: Vendor has not confirmed the flaw publicly but the version 5.0.9 is reportedly not vulnerable.
Council Site Actions: Only two reporting sites are using the affected software on UNIX platforms. They are not treating this as a high priority and will distribute the patches during their next regularly scheduled system update process.
Description: Exploit code has been publicly posted for the stack-based buffer overflow vulnerability in the libpng library, which was discussed in the last week's issue of the @RISK newsletter. The exploit code creates a malicious PNG file that can be posted to a website or sent as an email attachment. Opening this file via a browser or an email client may lead to execution of arbitrary code. Multiple vendors have already released patches for the libpng vulnerabilities, which should be applied on a priority basis. Council Site Actions: No new actions reported by the council site members. They have notified the affected users and advised them to patch as necessary or they are waiting on a patch from the vendor.
Description: Cfengine, or the "configuration engine", is used to build expert systems that administer and configure large computer networks of UNIX/Linux systems. The cfengine server (cfservd) contains a heap-based buffer overflow vulnerability in its RSA authentication module. The flaw can be exploited by an unauthenticated attacker to possibly execute arbitrary code with the privileges of the cfservd daemon, typically root. In a typical site configuration however, the central cfengine server only allows connections from systems that are being managed. Thus, an attacker would need to compromise or masquerade as one of these authorized systems in order to wage a successful attack. A proof of concept exploit has been publicly posted.
Status: Vendor confirmed, version cfengine-2.1.8 contains the fixes. Traffic to the cfengine server port (5308/tcp by default) can also be blocked at the network perimeter. Council Site Actions: The affected software is not in production or widespread use at any of the council sites. They reported that no action was necessary.
Description: CVSTrac server offers a web-based bug and patch tracking system for the CVS repositories. This server contains a remote command execution vulnerability. The flaw arises due to insufficient sanitization of the user-supplied input passed to the "filediff" cgi. An attacker can include shell metacharacters such as ";" in the parameter values, and execute arbitrary commands on the CVSTrac web server. The posted advisory shows how to craft the malicious HTTP commands.
Status: Vendor confirmed. Upgrade to version 1.1.4. Council Site Actions: The affected software is not in production or widespread use at any of the council sites. They reported that no action was necessary.
Description: Xine is a multimedia player for Linux systems that can play CDs, VCDs or DVDs. The player contains a stack-based overflow that can be triggered by a specially crafted media file. The problem occurs because xine does not perform a bounds checking on the source associated with the "vcd://" URL in a media file. A malicious media file posted on a website or attached to an email may exploit the flaw to execute arbitrary code on a client system. Exploit code has been publicly posted.
Status: Vendor confirmed, a fixed version of the source code can be downloaded via the CVS. Note that Xine ships by default with some flavors of Linux. Council Site Actions: The affected software is not in production or widespread use at any of the council sites. They reported that no action was necessary.
Description: An exploit has been posted for the CVS server ArgumentX command implementation vulnerability, which was discussed in a prior issue of the @RISK newsletter. The exploit reportedly works on Redhat 8.0, and spawns a command shell on port 30464/tcp. Council Site Updates: No actions reported by the council sites on this vulnerability.
Description: An exploit has been posted for the buffer overflow vulnerability in the Apple Filing Protocol. The exploit reportedly spawns a "root" shell on port 6969/tcp. Council Site Updates: Due to the late breaking nature of the issue, we could not solicit any council site responses.
Description: Microsoft has released the Service Pack 2 for Windows XP systems. The service pack is currently available in a form that can be used to update multiple Windows systems. The release that can update a single system is still awaited. This service pack offers enhanced security features to better protect users from worm attacks like Blaster and Sasser, Internet Explorer vulnerabilities and other malicious code. Council Site Actions: Most council sites have begun action on this Service Pack release. Most of these sites are doing regression testing to determine compatibility and have not yet set a deployment date. One site is currently deploying in stages and looking for incompatibilities. Another site is monitoring NTBugtraq to see what pain early implementers experience.
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 3651 unique vulnerabilities. For this special SANS community listing, Qualys also includes vulnerabilities that cannot be scanned remotely.
(c) 2004. 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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