Microsoft today released its September Patch Tuesday update, with Internet Explorer topping the list of vulnerabilities.
This month, Microsoft is patching 37 vulnerabilities in IE, of which 36 were reported privately and one was publicly disclosed. Ross Barrett, senior manager of security engineering at Rapid7, told eWEEK that the September IE patch addresses one publicly disclosed issue identified as CVE-2014-7331, which is under limited active attack.
"An information disclosure vulnerability exists in Internet Explorer which allows resources loaded into memory to be queried," a Microsoft security advisory states. "This vulnerability could allow an attacker to detect anti-malware applications in use on a target and use the information to avoid detection."
The CVE-2014-7331 issue is also particularly noteworthy because it is a different type of vulnerability than the other 36 that Microsoft is patching in IE this month, which are memory corruption issues.
"Remote code execution vulnerabilities exist when Internet Explorer improperly accesses objects in memory," Microsoft stated in its advisory. "These vulnerabilities could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user."
Craig Young, security researcher for Tripwire, told eWEEK that the CVE-2014-7331 vulnerability is also noteworthy in how it actually exploits a system.
"Unlike most IE information disclosures which are used to bypass ASLR [Address Space Layout Randomization] through memory address disclosure, this vulnerability utilizes a special URL scheme which allowed crafted Websites to determine if specific libraries are available," Young explained.
Young added that the presence or lack of a particular library is used to infer details about the target system's configuration, such as which security tools are installed.
"Armed with this information, the exploit kits can more carefully select which, if any, payload can be used without triggering endpoint protection," he said.
The September patch haul for IE overall is higher than it was for the August patch update, when 26 vulnerabilities were patched. As is the case this month, the bulk of the vulnerabilities were memory-related issues. Whether or not Microsoft can ever completely plug memory-related flaws in IE is a question that is difficult to answer.
"It sure doesn't seem like an end is in sight, does it? I've heard no indication that it is," Barrett said. "I think in practical terms, this has to trail off sometime, when most of the code base has been overhauled and all the use-after-free type issues have been addressed. However, I don't know when that will be."
While memory corruption issues are likely to remain a concern for some time, Microsoft is taking proactive steps to improve IE security overall. With the August Patch Tuesday update, Microsoft first introduced the capability in IE to block out-of-date ActiveX plug-ins in the browser. At the time, Microsoft said that the blocking feature would not become active for 30 days. Those 30 days are now up, and ActiveX blocking is part of the IE update.
"Applying strict controls around the use of out-of-date software is virtually a surefire way to increase the security of any system," Young said.
Young noted that one of the things that makes Google's Chrome browser robust from a security perspective is Google's attitude toward out-of-date plug-ins and browsers. Chrome has taken steps for a while to prevent users from activating out-of-date Java or Flash components.
"While these types of changes are not the enterprise-friendly policies we tend to see from Microsoft, it is a wise move in the right direction and certainly raises the bar for IE security,” Young said.
Sean Michael Kerner is a senior editor at eWEEK and InternetNews.com. Follow him on Twitter @TechJournalist.