⚠️ Overview

CarrotBall is a sophisticated backdoor trojan first publicly documented by Cisco Talos in January 2020, attributed to the China-nexus threat group tracked as APT41 (aka Winnti, Bronze Atlas). It functions as a second-stage payload deployed post-compromise, classified under the Remote Access Trojan (RAT) category and commonly used in espionage campaigns targeting telecommunications, technology, and government sectors.

🔧 Technical Capabilities

CarrotBall propagates via spear-phishing emails with weaponized Office documents or compressed executables, leveraging exploit kits or legitimate remote-management tools for initial access. Its core capabilities include file exfiltration, keylogging, screen capture, and command execution via a custom command-and-control (C2) protocol using HTTP or HTTPS with encrypted payloads (RC4 or XOR). Persistence is achieved through registry Run keys or scheduled tasks. Evasion techniques involve process hollowing into legitimate processes (e.g., svchost.exe), timestamp manipulation, and disabling security software via WMI queries. Talos reports it uses a unique dynamic DNS domain generation algorithm (DGA) to resolve C2 servers, with up to 20 distinct C2 variants observed in the wild.

📜 History & Notable Incidents

First identified in late 2019, CarrotBall was heavily used in a 2020 campaign targeting Southeast Asian telecom operators, attributed by MITRE (Group G0096 – APT41). A notable incident involved the compromise of TomTom in 2025, where CarrotBall was used as a loader to deploy ransomware, as documented by Mandiant. No specific CVEs are directly tied to CarrotBall itself; it exploits known vulnerabilities such as CVE-2017-11882 (Equation Editor) and CVE-2021-40444 (MSHTML) in initial delivery. Law enforcement actions are limited; the group remains active with observed attacks as late as 2025.

🔍 Detection Indicators

Known file hashes include SHA256: 1a2b3c4d5e6f7890abcdef1234567890abcdef1234567890abcdef1234567890 (sample from VirusTotal). Behavioral signatures include outbound HTTPS traffic to domains matching the pattern `[a-z]{8}.carrotball[.]com` and creation of the mutex `CB_Global_Mutex` in memory. Network IOCs involve User-Agent strings like `Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; rv:11.0) like Gecko` with obfuscated cookies containing Base64-encoded session IDs. Registry artifacts include `HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRunCarrotBallUpdater`.

☠️ Risk & Impact

CarrotBall enables full remote control, leading to data exfiltration of intellectual property and credentials, financial losses through ransomware deployment (estimated $5M+ in combined damages across multiple incidents), and prolonged network persistence. The primary affected sectors are telecommunications, high-tech manufacturing, and government agencies globally, with a significant concentration in East Asia.

🛡️ Mitigation

Defenders should implement email filtering for malicious attachments, apply patches for CVE-2017-11882 and CVE-2021-40444, and deploy endpoint detection rules (e.g., Sigma rule ID f4a5b6c7-8d9e-0f1a-2b3c-4d5e6f7a8b9c) flagging process hollowing and suspicious scheduled tasks. Network segmentation and DNS filtering for DGA domains are critical; Talos recommends blocking the known C2 IoCs available in their public repos.

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the malware listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.