Tripwire Security Researchers on MS Patch

In response to the recent Microsoft Patch, security experts Tripwire have made the following comments:

According to Tyler Reguly, technical manager of security research and development:

“IT pros everywhere will have a little less weight on their shoulders because Microsoft shipped a fix for the current IE zero-day. It’s important to note, however, that the fix is not in the traditional IE Cumulative Update (MS13-088) but rather in a separate ActiveX fix (MS13-090).

Also patched this month is GDI, and while the bulletin wouldn’t normally merit a critical rating, the vulnerability exists in a common API call that may be implemented by numerous third party products. In addition to applying today’s patches, keep an eye out for security updates from other vendors that make use of the built-in WIndows’ graphics libraries.

The more interesting patches this month are for a unique Outlook vulnerability that could allow port-scanning, a Hyper-V vulnerability that could allow Guest OS to Guest OS code execution, and an X.509 issue in schannel.dll that could allow denial of service. While these are unique and interesting vulnerabilities, they pose a lot less risk than typical code execution vulnerabilities.

It’s interesting that Microsoft released  an update for Direct Access that is not considered a ‘security update.’ The update resolves a known CVE, but Microsoft didn’t deem it worthy of a bulletin. Generally this implies the update is a functionality change in the software, rather than a pure security fix. While the process makes sense on paper, it makes it much more difficult for administrators to recognize that additional patches that actually resolve vulnerabilities are available for their systems. Regardless of the severity of the issue, not issuing a bulletin decreases security for users of Direct Access everywhere.”

According to Craig Young, security researcher:

“Without a doubt, the highest priority for most organizations will be to deploy the IE fix which blocks access to the InfoCard control being exploited in targeted watering-hole attacks. As critical as it is, the IE zero-day appears to be a run of the mill ActiveX memory corruption bug.

Some of the less critical but more technically interesting bugs include MS13-092 which can allow an administrator using a Hyper-V guest machine to crash the host or gain code execution privileges for  another guest.

MS13-094 can allow remote attackers to craft S/MIME emails for the purpose of running a port scan from a victim system. This is possible because when viewed in Outlook, the S/MIME message could trigger HTTP requests to arbitrary hosts/ports during signature validation.  The attacker can then perform a timing analysis to get an idea of which hosts/ports are accessible from the victim machine. This information can be leveraged in future attacks.  Microsoft resolved this issue by limiting the number of S/MIME signers processed.”