Windows administrators will want to block ports 42/tcp and 42/udp at the network perimeter, shut off the WINS service, or configure the WINS servers to use IPsec for database replication. Exploits are circulation (see #1 below) and Microsoft has no patch yet. You'll also want to roll out the December 1 Microsoft patch to all your Internet Explorer desktops. (See #2 below) 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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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: Microsoft Windows Internet Naming Service (WINS) provides a mapping between IP addresses and NETBIOS names. The replication service provided by the WINS can be used to replicate the WINS database amongst multiple WINS servers. The replication service, which runs on port 42/tcp, contains a memory overwrite flaw that can be triggered by a sequence of specially crafted packets. An attacker can exploit the memory overwrite to execute arbitrary code with "SYSTEM" privileges on the vulnerable server. The technical details about the flaw have been publicly posted. Exploit code is also available for the users of CORE Impact and ImmunitySec CANVAS products. Note that WINS service is not installed by default on Windows NT/2000/2003 servers with the exception of the Small Business server. However, WINS running on domain controllers (a likely configuration) may result in compromising an entire Windows domain.
Status: Microsoft is aware of the problem but has not issued any patch.A workaround is to block the ports 42/tcp and 42/udp at the network perimeter. Another workaround is to configure the WINS servers to use IPsec for database replication.
Council Site Actions: All reporting council sites are blocking ports42 TCP and UDP at their network perimeters and they are waiting for a patch from Microsoft. One site is researching the possibility of removing the service entirely (although unlikely). Another site is using host-base firewalls to block ports 42 TCP and UDP. One of the council sites is a customer of one of the companies that provides WINS exploit code in its product, thus they were able to confirm the vulnerability on a number of their systems. This was important because they did not want to impose requirements on their system administrators during the holiday weekend unless the vulnerability was actually known to be exploitable. They began notifying the system administrators on Friday afternoon November 26 and continued into the weekend. They also deployed IDS signatures for WINS attacks. Their WINS services were operating on servers in several of their larger departments, but their central IT department has never relied on or supported WINS. They suggested that the departments' main options were to use IP Security Policies on their servers to restrict access to port 42 to the necessary client IP addresses, or to shut off the WINS service. Shutting off WINS service was the popular choice.
Description: Microsoft released a cumulative security update for Internet Explorer (MS04-040) on December 1, 2004 prior to the regularly scheduled monthly updates. This update fixes a buffer overflow in Internet Explorer's processing of FRAME/IFRAME HTML tags, which has been discussed in the past @RISK newsletters. The flaw is currently being exploited in the wild by multiple viruses. Please ensure that the update is correctly installed as some reports indicate that a system is still vulnerable after installing the update via the "Automatic Updates"feature.
Council Site Actions: Patching is in progress for most of the reporting council sites. One site is currently QA'ing the patch and will deploy during their next regularly scheduled system update process. Another site has already updated their critical systems. Another site commented they are not planning to verify whether Automatic Updates result in correct installation of this update. They expect that Microsoft will release a new patch if it is verified if that Automatic Updates do not work correctly in this case.
Description: MailEnable, a Windows-based mail server, contains a stack-based buffer overflow in its IMAP server. An unauthenticated attacker can trigger the flaw by sending an overlong command string (over 8198 bytes). The flaw can be exploited to execute arbitrary code with the privileges of the IMAP server. Exploit code has been publicly posted.
Status: Vendor confirmed, hot fixes available.Council Site Actions:The affected software is not in production or widespread use, or is not officially supported at any of the council sites. They reported that no action was necessary.
Description: Ipswitch's WS_FTP server, a popularly used FTP server on Windows platforms, reportedly contains multiple buffer overflow vulnerabilities. An authenticated attacker ("anonymous" logins may work) can provide overlong arguments to FTP commands such as "SITE","MKD","XMKD" and "RNFR" and trigger the overflows. The flaws may be exploited to execute arbitrary code on the server with the privileges of the WS_FTP process, possibly "SYSTEM". Exploit code has been publicly posted.
Status: Vendor has been contacted; no patches available yet.
Council Site Actions: The affected software is not in production or widespread use, or is not officially supported at any of the council sites. They reported that no action was necessary.
Description: Jabber is an open-source protocol mainly used for instant messaging. jabberd, the Jabber server for Unix systems, reportedly contains a buffer overflow in its C2S (client to server) module. An unauthenticated attacker can provide an overlong username to trigger the overflow, and exploit the flaw to possibly execute arbitrary code on the jabber server. The problem arises because the attacker can bypass the username length checking. The technical details about the flaw are available.
Status: Vendor confirmed, patch available via CVS. If Jabber is used only internally in an organization, block the port 5222/tcp at the network perimeter.
Council Site Actions: The affected software is not in production or widespread use, or is not officially supported at any of the council sites. They reported that no action was necessary.
Description: Mercury/32, a mail server for Windows OS, reportedly contains multiple buffer overflows in its IMAP server. The flaws can be triggered by providing overlong arguments to 14 IMAP commands. An authenticated attacker may exploit the flaw to execute arbitrary code on the server with the privileges of the Mercury/32 process. Exploit code is publicly available.
Status: Vendor confirmed, upgrade to version 4.01b.
Council Site Actions: The affected software is not in production or widespread use, or is not officially supported at any of the council sites. They reported that no action was necessary.
Description: Exploit code has been publicly posted for the flaw in PHP when configured with the "memory_limit" directive. The flaw can be exploited to execute arbitrary code on a web server running PHP.
Council Site Actions: Only two of the reporting council sites provided an update for this item. One site is waiting on a response from the vendor. The other site has patched all of their Red Hat and Debian systems, but still has some Mac OX X systems running Apache web servers with PHP. They don't believe that Apple has issued a PHP update. They were considering referring their Mac OS X PHP users to the Web site for binary downloads of PHP 5.0.2 ( http://www.php.net/downloads.php links to http://www.entropy.ch/software/macosx/php/), but the Web site contains a message "The main www.entropy.ch server/website was hacked and defaced on December 1st". They will most likely suggest compiling PHP 5.0.2 or 4.3.9 from the source code.
Description: A variation of the Internet Explorer "Drag and Drop"exploit code has been published. This exploit requires lesser user interaction than the previously posted one. Note that this vulnerability is still unpatched.
Council Site Actions: All council sites are still waiting on a response or workaround from the vendor.
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 3893 unique vulnerabilities. For this special SANS community listing, Qualys also includes vulnerabilities that cannot be scanned remotely.
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