Zscaler ThreatLabz security researchers are watching hackers move to a new open source command and control (C2, C&C) platform called Havoc as an alternative to Cobalt Strike.
Among the most interesting features of Havoc is cross-platform: it bypasses Microsoft Defender on modern devices with Windows 11 using the Sleep obfuscation method, return address stack substitution, and indirect system calls.
Like other exploit kits, Havoc includes a wide range of modules that allow pentesters and hackers to perform a variety of tasks on exploited devices, including:
- execution of commands;
- process management;
- loading additional payload data;
- manipulating Windows tokens;
- shellcode execution.
All this is done through a control panel that allows an attacker to see all compromised devices, events, and task outputs.
Recently, in early January, an unknown threat group used this post-exploitation kit as part of a campaign against an unnamed government organization.
The Zscaler ThreatLabz research team observed that the shellcode loader dropped on compromised systems disables event tracking for Windows (ETW), and the final Havoc Demon payload is loaded without the "DOS" and "NT" headers to avoid detection.
The framework was also deployed using the malicious npm package "Aabquerys", whose name uses the Typosquatting method to imitate a legitimate module.
“Demon.bin is a malicious agent with typical features of a RAT Trojan that was generated using Havoc. It supports the creation of malicious agents in several formats, including Windows PE executable, PE DLL, and shellcode.
Cobalt Strike has become the most common tool for hackers to deliver additional payloads, but some cybercriminals have begun to look for alternatives to this tool as defenders have learned to better detect and prevent attacks.
One alternative is Brute Ratel (BRc4), which is a complex set of tools "to avoid detection of EDR solutions and antivirus software." Created by Indian cybersecurity specialist Chetan Nayak, the BRc4 is an analogue of Cobalt Strike and is described as "a customizable command and control center for the Red Team and enemy emulation."
Another free replacement for Cobalt Strike that has become very popular on the dark web is Sliver, a cross-platform, open-source Go-based penetration testing tool developed by security company BishopFox. C&C Server Sliver supports multiple protocols (DNS, HTTP/TLS, MTLS, TCP) and implant connection, and can host files that mimic a legitimate web server. Therefore, information security specialists can set up listeners to detect the Sliver infrastructure on the darknet.