Gandcrab — RTF malware analysis

Static analysis result for SHA-256 a0db7d48dff31fc4…

MALICIOUS

RTF

852.6 KB First seen: 2019-03-18
MD5: 38d03214fcbcb93dbdbf94be22a7067c SHA-1: 083869b0a37a9c0aea3a9246b8c2b5937f59027e SHA-256: a0db7d48dff31fc414202e95701c4c0326e6692a2a2a02d7f3d807f18390dc18
424 Risk Score

Malware Insights

Gandcrab · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple critical heuristic firings indicating the exploitation of CVE-2017-8570 through an embedded OLE object, specifically leveraging the Equation Editor. ClamAV detections confirm this as Win.Dropper.Gandcrab-7077551-0, suggesting it acts as a dropper for the Gandcrab ransomware. The embedded OLE object likely contains shellcode or a script designed to download and execute the final payload.

Heuristics 10

  • Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570
    RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • ClamAV: Win.Dropper.Gandcrab-9828787-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Dropper.Gandcrab-9828787-0
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 7 \objdata section(s) — embedded OLE objects
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://nsis.sf.net/NSIS_Error In RTF body

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000031.bin rtf-objdata-decoded RTF \objdata at offset 0x31 366018 bytes
SHA-256: 97931cf609170b9846995fca73f6548405318bec83807546c46ee2f027196011
Detection
ClamAV: Win.Dropper.Gandcrab-9828787-0
Obfuscation or payload: likely
Carved artifact entropy is 7.96, consistent with packed or encrypted content.
objdata_01_off000cb21b.bin rtf-objdata-decoded RTF \objdata at offset 0xCB21B 11418 bytes
SHA-256: 46f9bc269fbb243155382255bba723f85a09e3b4920455f18b20c83ef0163078
objdata_02_off000d0b87.bin rtf-objdata-decoded RTF \objdata at offset 0xD0B87 473 bytes
SHA-256: f3095aa78550aed010de364ce63661ed32aa929baefb923d39ef555ebe6515da
objdata_03_off000d0f75.bin rtf-objdata-decoded RTF \objdata at offset 0xD0F75 834 bytes
SHA-256: 69d7869592bad1ec2c7ab81989c2c7e08fc2efd3821c52314c76f5e9a3feddaa
objdata_04_off000d1677.bin rtf-objdata-decoded RTF \objdata at offset 0xD1677 2247 bytes
SHA-256: 992c836552ac8953ea96f98fe3fdf2f015904931030078610b1ec4c608451d62
objdata_05_off000d289b.bin rtf-objdata-decoded RTF \objdata at offset 0xD289B 4679 bytes
SHA-256: a031167f29c59aa6f60f009231ba4b3342834ba008154b405252e98bc2ed362a

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