Posts Tagged: Internet Explorer zero-day


11
Aug 20

Microsoft Patch Tuesday, August 2020 Edition

Microsoft today released updates to plug at least 120 security holes in its Windows operating systems and supported software, including two newly discovered vulnerabilities that are actively being exploited. Yes, good people of the Windows world, it’s time once again to backup and patch up!

At least 17 of the bugs squashed in August’s patch batch address vulnerabilities Microsoft rates as “critical,” meaning they can be exploited by miscreants or malware to gain complete, remote control over an affected system with little or no help from users. This is the sixth month in a row Microsoft has shipped fixes for more than 100 flaws in its products.

The most concerning of these appears to be CVE-2020-1380, which is a weaknesses in Internet Explorer that could result in system compromise just by browsing with IE to a hacked or malicious website. Microsoft’s advisory says this flaw is currently being exploited in active attacks.

The other flaw enjoying active exploitation is CVE-2020-1464, which is a “spoofing” bug in virtually all supported versions of Windows that allows an attacker to bypass Windows security features and load improperly signed files. For more on this flaw, see Microsoft Put Off Fixing Zero for 2 Years.

Trend Micro’s Zero Day Initiative points to another fix — CVE-2020-1472 — which involves a critical issue in Windows Server versions that could let an unauthenticated attacker gain administrative access to a Windows domain controller and run an application of their choosing. A domain controller is a server that responds to security authentication requests in a Windows environment, and a compromised domain controller can give attackers the keys to the kingdom inside a corporate network.

“It’s rare to see a Critical-rated elevation of privilege bug, but this one deserves it,” said ZDI’S Dustin Childs. “What’s worse is that there is not a full fix available.”

Perhaps the most “elite” vulnerability addressed this month earned the distinction of being named CVE-2020-1337, and refers to a security hole in the Windows Print Spooler service that could allow an attacker or malware to escalate their privileges on a system if they were already logged on as a regular (non-administrator) user.

Satnam Narang at Tenable notes that CVE-2020-1337 is a patch bypass for CVE-2020-1048, another Windows Print Spooler vulnerability that was patched in May 2020. Narang said researchers found that the patch for CVE-2020-1048 was incomplete and presented their findings for CVE-2020-1337 at the Black Hat security conference earlier this month. More information on CVE-2020-1337, including a video demonstration of a proof-of-concept exploit, is available here. Continue reading →


12
Nov 19

Patch Tuesday, November 2019 Edition

Microsoft today released updates to plug security holes in its software, including patches to fix at least 74 weaknesses in various flavors of Windows and programs that run on top of it. The November updates include patches for a zero-day flaw in Internet Explorer that is currently being exploited in the wild, as well as a sneaky bug in certain versions of Office for Mac that bypasses security protections and was detailed publicly prior to today’s patches.

More than a dozen of the flaws tackled in this month’s release are rated “critical,” meaning they involve weaknesses that could be exploited to install malware without any action on the part of the user, except for perhaps browsing to a hacked or malicious Web site or opening a booby-trapped file attachment.

Perhaps the most concerning of those critical holes is a zero-day flaw in Internet Exploder Explorer (CVE-2019-1429) that has already seen active exploitation. Today’s updates also address two other critical vulnerabilities in the same Windows component that handles various scripting languages.

Microsoft also fixed a flaw in Microsoft Office for Mac (CVE-2019-1457) that could allow attackers to bypass security protections in some versions of the program.

Macros are bits of computer code that can be embedded into Office files, and malicious macros are frequently used by malware purveyors to compromise Windows systems. Usually, this takes the form of a prompt urging the user to “enable macros” once they’ve opened a booby-trapped Office document delivered via email. Thus, Office has a feature called “disable all macros without notification.”

But Microsoft says all versions of Office still support an older type of macros that do not respect this setting, and can be used as a vector for pushing malwareWill Dormann of the CERT/CC has reported that Office 2016 and 2019 for Mac will fail to prompt the user before executing these older macro types if the “Disable all macros without notification” setting is used. Continue reading →


19
Sep 12

Microsoft Issues Stopgap Fix for IE 0-Day Flaw

Microsoft today released a stopgap fix for a critical security flaw in most versions of Internet Explorer that hackers have been exploiting to break into Windows systems. The company said it expects to issue an official patch (MS12-063) for the vulnerability on Friday, Sept. 21.

The company released a “fix it” tool, available from this link, designed to blunt the threat of attack on this flaw for users of IE 7, 8 and 9. In a blog post, Microsoft’s Yunsun Wee said the one-click solution should not affect users’ ability to browse the Web, and it does not require the reboot of your computer. Users should not need to uninstall the fix to apply the full security patch when Microsoft releases it.

I’m glad to see Microsoft take this step. The company keeps downplaying the threat, stating that “there have been an extremely limited number of attacks,” against that this flaw and that “the vast majority of Internet Explorer users have not been impacted.” Nevertheless, as I noted in previous stories this week, a reliable exploit for this vulnerability has already been rolled into free, easy-to-use attack tools, so IE users should not delay in applying this fix-it tool.

For more information on how to harden IE against attacks, see Internet Explorer Users, Please Read This.


17
Sep 12

Exploit Released for Zero-Day in Internet Explorer

A working exploit that takes advantage of a previously unknown critical security hole in Internet Explorer has been published online. Experts say the vulnerability is being actively exploited in the wild, and that it appears to be connected to the same group of Chinese hackers responsible for unleashing a pair of Java zero-day exploits late last month.

Researchers at security vulnerability testing firm Rapid7 have added a new module to the company’s free Metasploit framework that allows users to successfully attack the vulnerability on Internet Explorer versions 7, 8 and 9 on Windows XP, Vista and 7.

“Computers can get compromised simply by visiting a malicious website, which gives the attacker the same privileges as the current user,” Rapid7 researcher “sinn3r” wrote on the firm’s blog. “Since Microsoft has not released a patch for this vulnerability yet, Internet users are strongly advised to switch to other browsers, such as Chrome or Firefox, until a security update becomes available. The exploit had already been used by malicious attackers in the wild before it was published in Metasploit. The associated vulnerability puts about 41% of Internet users in North America and 32% world-wide at risk.”

News of the IE exploit surfaced at the blog of security researcher and blogger Eric Romang, who said he discovered the attack code while examining a Web server recently used by Chinese hackers to launch targeted attacks via zero-day Java vulnerabilities that were patched by Oracle last month. Romang and other experts have connected the sites serving those Java exploits to the Nitro attacks of 2011, espionage attacks directed against at least 48 chemical and defense companies.

I pinged Microsoft for a comment but have not yet heard back from them. I suspect they are preparing an advisory about this threat, and will update this post when I receive a response. Until an official fix is available, IE users would be wise to surf with another browser.