Adobe Issues Out-of-Band Patch for Critical Flash Player Vulnerability (CVE-2018-15981)

Adobe has released an out-of-band patch for a critical Flash Player vulnerability. Users are encouraged to upgrade as soon as possible.

Contexte

On November 20, Adobe released APSB18-44, an out-of-band (OOB) security bulletin to address a zero day vulnerability in Adobe Flash Player versions 31.0.0.148 and earlier for Windows, macOS, Linux and Chrome OS.

This bulletin arrived seven days after Adobe released APSB18-39, it’s monthly security bulletin for November 2018. On the very same day, November 13, researcher Gil Dabah published a blog discussing his discovery of CVE-2018-15981.

It may not seem like a coincidence that both Adobe’s monthly security bulletin and the researcher’s blog were published on the same day. However, Dabah indicated it may just have been a coincidence after all in a tweet:

Kudos to @AdobeSecurity for touching base and working on a fix already.

— Gil Dabah (@_arkon) November 14, 2018

Vulnerability details

In his blog, Dabah shares details about CVE-2018-15981, a type confusion vulnerability in Adobe Flash Player. Specifically, the vulnerability exists in the interpreter code for Adobe’s ActionScript Virtual Machine (AVM). According to Dabah, the AVM’s interpreter “does not reset a with-scope pointer when an exception is caught” which leads to the type confusion and “eventually to a remote code execution.”

User interaction is required to exploit this vulnerability. An attacker would need to convince users to visit a malicious website, compromise a website or advertising network and inject malicious code.

For further technical details about the vulnerability, please visit Dabah’s blog.

Urgently required actions

Upgrade to the latest version of Flash Player for your respective operating system or web browser. Adobe has provided links in the solution section of their security bulletin.

If Adobe Flash is not a requirement in your network or on your devices, you may consider disabling it altogether.

Identification des systèmes affectés

A list of Nessus plugins to identify this vulnerability will appear here as they’re released.

En savoir plus 

• Security updates available for Flash Player | APSB18-44
• Flash News (Gil Dabah's blog)
• ADV180030 | November 20, 2018 Flash Updates

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