Threat Advisory

COLDRIVER APT Uses BAITSWITCH and SIMPLEFIX to Deliver Malware

Threat: Malicious Campaign
Threat Actor Name: Callisto Group
Threat Actor Type: -
Targeted Region: Global
Alias: Gossamer Bear, UNC4057, Seaborgium, Star Blizzard, TA446, TAG-53, BlueCharlie, Cobalt Edgewater, Iron Frontier, Blue Callisto, Cold River, Coldriver, BlueCharlie
Threat Actor Region: Russia
Targeted Sector: Technology & IT
Criticality: High
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EXECUTIVE SUMMARY

Researchers found a multi-stage ClickFix campaign that aimed at people linked to Russian civil society. The attackers used a fake checkbox on a webpage to trick users into copying a command to the clipboard and pasting it into the Windows Run box. When run, the command launched a downloader DLL called BAITSWITCH. The webpage also showed a decoy document with content meant to look relevant and trustworthy, which likely helped convince targets to follow the on-screen steps. The campaign used checks on the server side to only deliver malicious content to systems that matched specific traits, making the attacks selective rather than broad.[/subscribe_to_unlock_form]

EXECUTIVE SUMMARY

Researchers found a multi-stage ClickFix campaign that aimed at people linked to Russian civil society. The attackers used a fake checkbox on a webpage to trick users into copying a command to the clipboard and pasting it into the Windows Run box. When run, the command launched a downloader DLL called BAITSWITCH. The webpage also showed a decoy document with content meant to look relevant and trustworthy, which likely helped convince targets to follow the on-screen steps. The campaign used checks on the server side to only deliver malicious content to systems that matched specific traits, making the attacks selective rather than broad.[emaillocker id="1283"]

The choice of content and the social setup around the fake checkbox show the campaign relied heavily on tricking people rather than on highly complex code. The infection chain begins when the user executes a command that runs machinerie.dll, the BAITSWITCH downloader. BAITSWITCH makes several web requests to a threat-controlled domain using a hardcoded browser-like user-agent. Based on responses it receives, it runs commands to set persistence, store encrypted data in the registry, download a PowerShell stager to the user profile, and erase traces from the RunMRU list. On the next login the stager runs and uses basic string hiding and Base64 decoding to reconstruct the full script.

That script then launches SIMPLEFIX, a PowerShell backdoor that wakes every few minutes, builds a custom user-agent from local system data, checks in with a remote server for tasks, executes received commands, and reports back when tasks finish. The campaign also split decryption data across different delivery methods so the final payload could not be trivially extracted from a single place. This campaign shows that social tricks plus light-weight tools can still succeed at gaining access and running commands on target machines. The attackers focused on convincing users to take a single action that triggered the whole chain, then used small, scripted tools to keep control and run tasks from afar. The selective delivery and simple hiding steps helped reduce noise and made the operation harder to spot at a glance While the tools used are not highly complex, the overall design – a convincing lure, staged downloads, and periodic checks – made the campaign effective against the chosen targets. The main takeaway is that human-focused traps remain a powerful route for attackers, and even modest malware can do a lot when combined with carefully crafted social engineering.

THREAT PROFILE:

Tactic Technique ID Technique Sub-technique
Resource Development T1583.001 Acquire Infrastructure Domains
Resource Development T1583.006 Acquire Infrastructure Web Services
Resource Development T1585.002 Establish Accounts Email Accounts
Resource Development T1585.003 Establish Accounts Cloud Accounts
Resource Development T1587.001 Develop Capabilities Malware
Resource Development T1608.001 Stage Capabilities Upload Malware
Resource Development T1608.003 Stage Capabilities Install Digital Certificate
Resource Development T1608.005 Stage Capabilities Link Target
Execution T1204.004 User Execution Malicious Copy and Paste
Execution T1059.001 Command and Scripting Interpreter PowerShell
Execution T1059.003 Command and Scripting Interpreter Windows Command Shell
Persistence T1037.001 Boot or Logon Initialization Scripts Logon Script (Windows)
Persistence T1112 Modify Registry Modify Registry
Defense Evasion T1140 Deobfuscate/Decode Files or Information
Defense Evasion T1564.003 Hide Artifacts Hidden Window
Defense Evasion T1218.011 System Binary Proxy Execution Rundll32
Defense Evasion T1205 TrafficSignaling
Defense Evasion T1070.003 Indicator Removal Clear Command History
Defense Evasion T1027.011 Obfuscated Files or Information Fileless Storage
Defense Evasion T1027.013 Obfuscated Files or Information Encrypted/Encoded File
Discovery T1033 System Owner/User Discovery
Discovery T1082 System Information Discovery
Discovery T1135 Network Share Discovery
Discovery T1016 System Network Configuration Discovery
Discovery T1016.001 System Network Configuration Discovery Internet Connection Discovery
Discovery T1087.001 Account Discovery Local Account
Discovery T1083 File and Directory Discovery
Discovery T1049 System Network Connections Discovery
Discovery T1057 Process Discovery
Discovery T1018 Remote System Discovery
Discovery T1046 Network Service Discovery
Discovery T1124 System Time Discovery
Collection T1005 Data from Local System
Collection T1530 Data from Cloud Storage
Command and Control T1071.001 Application Layer Protocol Web Protocols
Command and Control T1104 Multi‐Stage Channels
Command and Control T1001.003 Data Obfuscation Protocol or Service Impersonation
Command and Control T1105 Ingress Tool Transfer
Command and Control T1132.001 Data Encoding Standard Encoding
Command and Control T1573.002 Encrypted Channel Asymmetric Cryptography

REFERENCES:

The following reports contain further technical details:
https://cybersecuritynews.com/coldriver-apt-group-uses-clickfix/
https://www.zscaler.com/blogs/security-research/coldriver-updates-arsenal-baitswitch-and-simplefix

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