This site uses cookies. By continuing to browse this site you are agreeing to our use of cookies. Find out more.X

Internet Explorer flaw was being actively exploited ahead of last Patch Tuesday

Share this article:

An Internet Explorer vulnerability was patched after being actively exploited in the wild.

According to M86 Security, remote code execution vulnerability CVE-2011-1255, which was patched last month as part of bulletin MS11-050, was being exploited before Microsoft released details about the particular vulnerability.

M86 Security's Avri Schneider said that the company was asked to inspect the URL of a legitimate website of a large private company that was blocked by one of the proactive detection rules implemented in its Secure Web Gateway product.

“After further inspection, we saw that it exploited an unpublished security vulnerability in Internet Explorer. To verify this, we viewed the malicious page on the latest fully patched version of IE and saw a crash followed by execution of malicious code,” he said.

“Based on data we have reviewed from various sources, we can say with a high level of certainty, that the anonymous researcher who (according to Microsoft's security advisory) reported the vulnerability details to VeriSign iDefense, or at least one of his acquaintances, had used the vulnerability details for malicious purposes, as part of targeted attacks.”

The ‘CISSP 2 CISSP' blog said that the compromise looked ‘like the same server used to serve the payload in this attack was used last year to exploit a different zero-day IE vulnerability (CVE-2010-0806)'.

“Because the attacker used an obfuscation method that relies on inserting shell code in the document object model (DOM) via a div element, the M86 researchers were able to use Google to discover over a dozen compromised websites serving this exploit,” it said.

“It is very likely that this vulnerability will be included in drive-by download kits and exploited for some time to come. Symantec has already reported attacks that targeted this vulnerability after Microsoft patched it.

“The malware installed as a result of successful exploitation in Symantec's report is a Trojan that connects to a remote server via HTTP and awaits further instructions.”

Symantec detected the Trojan as Trojan.Shixploit with the payload detected as Backdoor.Trojan since January 2010.

Writing three days after the patch was released, Symantec's Joji Hamada said that the only exploits seen affected Internet Explorer 8. “So far, we have only seen limited attacks taking advantage of this vulnerability and believe that the exploit is only being carried out in targeted attacks at present.”

Share this article:

SC webcasts on demand

This is how to secure data in the cloud

Exclusive video webcast & Q&A sponsored by Vormetric

As enterprises look to take advantage of the cloud, they need to understand the importance of safeguarding their confidential and sensitive data in cloud environments. With the appropriate security safeguards, such as fine-grained access policies, a move to the cloud is as, or more, secure than an on-premise data storage.

View the webcast here to find out more

More in News

Microsoft warns on yet another zero-day security flaw

Microsoft warns on yet another zero-day security flaw

Microsoft has warned Windows users about a zero-day security issue with malicious PowerPoint documents being emailed to recipients. The software giant is working on a patch for the problem.

Google launches FIDO-compliant 2FA USB key for Chrome and Gmail

Google launches FIDO-compliant 2FA USB key for Chrome ...

Google has souped up its two-factor authentication (2FA) login process with the launch of Security Key, a physical USB that only works after verifying the login site is truly a ...

Evolving TorrentLocker ransomware generating big money

Evolving TorrentLocker ransomware generating big money

The TorrentLocker ransomware has returned with a vengeance and is starting to bring in big money for its operators.