Adobe released a Flash Player update late last week to patch a Zero Day vulnerability where attackers were able to deliver malware via the Magnitude exploit kit.
The vulnerability, a memory corruption that can end up exploited for remote code execution, ended up discovered April 2 after security researcher Kafeine of Proofpoint noticed a change in the Magnitude exploit kit.
FireEye then analyzed the sample and determined Magnitude EK had been exploiting a previously unknown vulnerability in Flash Player.
The flaw is in Flash Player 22.214.171.124 and earlier, but a mitigation introduced by Adobe in March in version 126.96.36.199 prevents exploitation.
Adobe fixed the hole with the release of Flash Player 188.8.131.52, which also addresses 23 other issues.
Attackers took advantage of the exploit to target systems running Flash Player 184.108.40.2066 and earlier on Windows 10 and earlier.
“In the course of our investigation, we shared our findings with fellow researchers in the security community in order to accelerate identification of the exploit. A colleague at FireEye determined that the exploited vulnerability was unknown, Proofpoint said in a blog post. “Despite the fact that this new exploit could potentially work on any version of Adobe Flash, including a fully patched instance of Flash, the threat actors implemented it in a manner that only targeted older versions of Flash. In other words, equipped with a weapon that could pierce even the latest armor, they only used it against old armor, and in doing so exposed to security researchers a previously unreported vulnerability.”
Proofpoint said the exploit has been used by Magnitude to deliver various threats, including Cerber and Locky ransomware.
Researchers found the exploit code for this Flash Player Zero Day has also been added to the Nuclear Pack exploit kit.