In ongoing efforts to monitor and analyze emerging cyber threats, Morphisec Threat Labs has recently turned its focus to Chae$ 4.1, an update to the Chaes malware Infostealer series. This version introduces key updates, including an improved Chronod module, and features a unique aspect: a direct message to the Morphisec team within the source code.
This blog post will briefly touch upon the updates in Chae$ 4.1 and mention Morphisec’s initial interaction with the hackers. It will also cover several previously unknown details of the delivery chain.
For those interested in an in-depth technical analysis, we have prepared a comprehensive report on Chae$ 4.1, available for download.
Download the full Chae$ 4.1 technical analysis containing exclusive details.
The Chae$ authors dedicated parts of their source code to the Morphisec researchers
The infection chain starts with an email written in Portuguese, which purports to be an urgent communication request from a lawyer regarding a legal case. The email pressured the victim with an urgent call for “prompt response”, or risk highly adverse legal repercussions. The email includes a link and a password to access the document from that link.
Upon clicking the provided link, the victim will be redirected to https://totalavprotection[.]shop/abrirProcesso.php?email=<victims_email>. Then, the victim will be prompted to input the provided password to download the document, which is a ZIP file. This website https://totalavprotection[.]shop additionally functions as a deceptive website for TotalAV, directly delivering the MSI installer without the intermediary step of a ZIP file.
Yet another website delivers the malicious payload directly as an MSI installer. https://www.webcamcheck[.]online/ A website that allegedly scans the machine for risks and suggests updating the machine’s driver after “scanning”. After the victim clicks the BLOCK button (marked in red), a JavaScript is executed in the background. The script is designed to mimic the appearance of a legitimate system scan. During the simulated scan, a hardcoded list of files is presented, giving the illusion of a comprehensive analysis of the victim’s computer.
Following the scan, the victim is then shown with a crafted message: “Security Risk Detected” and urges the victim to download an updated driver to install the latest version and eliminate the risk.
Clicking the button triggers the execution of a script named download.js. Whose purpose is to smuggle the malicious installer by decoding a zipped base64 blob. Following the activation of the installer, Chae$ 4.1 is activated.
From this point onward, the attack chain remains similar to Morphisec’s previous analysis, except for some adjustments in the Chae$ framework. It has advanced from version 4 to 4.1, primarily characterized by modifications in the Chronod module.
In fact, the advancement to Chae$ 4.1 is clearly shown in debug messages:
Following successful activation, exfiltrated data is delivered to the threat actor’s C2. Examining the C2s employed throughout distinct phases of the framework unveils the presence of the Chae$ team panel login page.
The attached report dives deeper into the new Chae$ variant. Read the full Chae$ 4.1 analysis to delve deeper into the mechanics of this evolved malware, its implications, and what businesses can do to safeguard themselves.
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If you don’t believe us, ask the Chae$ group:
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