Security Experts:

Adobe Patches Disclosed Acrobat Vulnerability

Adobe has released Patch Tuesday updates for Flash Player, Acrobat and Reader, and Photoshop CC to address three vulnerabilities – one in each product.

The most interesting update is for the Windows version of Acrobat and Reader. It addresses an information disclosure vulnerability for which a proof-of-concept (PoC) exploit is already publicly available.

According to Adobe, exploitation of the flaw, tracked as CVE-2018-15979, “could lead to an inadvertent leak of the user’s hashed NTLM password.”

The security hole, credited by Adobe to free exploit detection service EdgeSpot, has been classified as “important severity,” but it has been assigned a priority rating of “1,” which indicates that there is a high risk of exploitation.

This is not the first time we hear of an Acrobat vulnerability that can be exploited to obtain NTLM credentials. In April, Check Point disclosed the details of a similar vulnerability, tracked as CVE-2018-4993, that could have been exploited by injecting malicious content into a PDF which would cause NTLM hashes to be automatically leaked when the file was opened. Adobe initially said it did not plan on releasing a fix, but a few weeks later it decided to release patches and mitigations.

Since in both cases Adobe has pointed users to the same mitigations, it’s possible that EdgeSpot has identified a new variant of CVE-2018-4993 and the previously published PoC can be easily adapted. SecurityWeek has reached out to EdgeSpot and Adobe for clarifications and will update this article if they respond.

The vulnerability patched on Tuesday in Flash Player, identified as CVE-2018-15978, is an out-of-bounds read bug that can lead to information disclosure. The issue affects the Windows, macOS, Linux and Chrome OS versions of Flash Player, but Adobe does not expect to see it being exploited any time soon.

Finally, Adobe has released updates for the Windows and macOS versions of Photoshop CC to address an out-of-bounds read bug that can lead to information disclosure. The vulnerability was reported to the tech giant by an anonymous researcher via Trend Micro’s Zero Day Initiative (ZDI).

Adobe says there is no evidence that any of these vulnerabilities have been exploited for malicious purposes.

Earlier this month, researchers warned that malicious actors had been exploiting a recently patched Adobe ColdFusion vulnerability to hack websites.

UPDATE. EdgeSpot has published a blog post confirming that the new Acrobat vulnerability (CVE-2018-15979) exists because Adobe failed to properly patch the flaw discovered earlier by Check Point (CVE-2018-4993).

Related: Adobe Patches Vulnerabilities in Flash Player, ColdFusion

Related: Adobe Patches Flash Zero-Day Exploited in Targeted Attacks

Related: Over 100 Vulnerabilities Patched in Adobe Acrobat, Reader

view counter
Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.