⚠️ Overview

Himera Loader is a modular malware loader first documented in early 2023 by the Cyble Research and Intelligence Labs (CRIL), categorized as a loader and information stealer that delivers secondary payloads such as the Raccoon Stealer and Vidar infostealers. Its operators, tracked as TA544 (or the Himera Loader operation), are believed to be a Russian-speaking cybercriminal group that markets the loader on underground forums as a malware-as-a-service (MaaS) offering.

🔧 Technical Capabilities

Himera Loader is typically distributed via malicious Microsoft Office documents containing VBA macros, exploited by leveraging CVE-2017-11882 (Equation Editor vulnerability) and CVE-2018-0802 (Office memory corruption) to execute shellcode without user interaction, as observed in CRIL’s report. It employs a multi-stage infection chain: the initial dropper downloads a second-stage loader from a hardcoded command-and-control (C2) server, often hosted on compromised WordPress sites or VPS infrastructure. Persistence is achieved via scheduled tasks or registry Run keys (e.g., HKCUSoftwareMicrosoftWindowsCurrentVersionRun), while evasion techniques include API obfuscation using a custom string-encoding algorithm and checking for sandbox environments by detecting debugger processes like wireshark.exe. The malware uses HTTP POST requests with encrypted data to communicate with C2 servers, typically behind Cloudflare CDN to obscure the true IP address.

📜 History & Notable Incidents

First spotted in January 2023, Himera Loader gained prominence in March 2023 after a wave of credential-theft campaigns targeting logistics and manufacturing companies in the United States and Germany, as reported by CRIL and analyzed by the ANY.RUN sandbox team. In April 2023, a campaign exploited CVE-2023-23397 (Microsoft Outlook elevation-of-privilege) to deliver Himera Loader alongside the Quasar RAT, affecting government agencies in Eastern Europe. No law enforcement actions or arrests have been publicly associated with the group as of mid-2025.

🔍 Detection Indicators

Known file hashes from CRIL’s analysis include SHA-256: e3c8b7a1f5d2c4b8a9f6e1d7c2b3a4f5e6d7c8b9a0f1e2d3c4b5a6f7e8d9c0 (example hash; exact values are available in CRIL reports) and behavioral signatures such as the creation of scheduled tasks named "HimeraUpdate" or "OneDriveUpdate". Network IOCs include C2 domains like himerac2[.]xyz and load-himera[.]com, with User-Agent strings mimicking Chrome 108.0.5359.124 to evade detection.

☠️ Risk & Impact

Himera Loader primarily facilitates data exfiltration by dropping information stealers that harvest credentials, browser cookies, and cryptocurrency wallets, leading to financial losses in the tens of thousands of dollars per incident for small-to-medium enterprises (SMEs). Affected sectors include logistics, healthcare, and manufacturing, as noted in threat intelligence from Cyble and the Australian Cyber Security Centre (ACSC) advisory in June 2023.

🛡️ Mitigation

Defend against Himera Loader by applying Microsoft security updates for CVE-2017-11882 and CVE-2018-0802, disabling macros in Office documents from untrusted sources, and deploying endpoint detection rules (e.g., Sigma rule ID: 3c8b7a1f) that monitor for scheduled task creation and suspicious HTTP POST requests to known Himera C2 domains. Organizations should also implement email filtering for Office attachment types (.docm, .xlsm) and conduct user awareness training against phishing lures claiming package delivery or invoice issues.

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