detect-cyzfc-activity

These queries was originally published in the threat analytics report, Attacks on gov't, think tanks, NGOs. As described further in Analysis of cyberattack on U.S. think tanks, non-profits, public sector by unidentified attackers, there was a very large spear-phishing campaign launched in November 2019. The attackers would gain access to a target by having the user click on a link to a compromised website and download a .zip archive. Once established on a target's device, the attackers used a malicious DLL named cyzfc.dat to execute additional payloads. They would call a function in the malicious DLL via the legitimate Windows process, rundll32.exe, to connect directly to their command-and-control (C2) servers. The following queries detect activity associated with the malicious DLL, cyzfc.dat., used in this campaign. Reference - https://docs.microsoft.com/windows-server/administration/windows-commands/rundll32