Malicious RTF — malware analysis report

Static analysis result for SHA-256 a1a71a8fdab52611…

MALICIOUS

RTF

264.4 KB Authoring application: Riched20 6.3.9600 First seen: 2020-09-15
MD5: bc39356175a827522cb8c46cb2c8d299 SHA-1: f8fe11eca31ab33756695244c1389115c3e1df9d SHA-256: a1a71a8fdab52611aa557847971d66be4126b50d7edea4344cf6d7d3b959d920
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains OLE objects and triggers CVE-2017-8570, indicating it's designed to execute arbitrary code. The heuristic 'CVE_2017_8570: Composite Moniker' specifically points to the exploitation of this vulnerability, which is known to drop SCT scripts. The document body appears to be a commercial invoice, likely used as a lure.

Heuristics 7

  • 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.
  • 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.
  • \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.
  • Suspicious extracted artifact high 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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000018bf.bin rtf-objdata-decoded RTF \objdata at offset 0x18BF 37572 bytes
SHA-256: 1cace296b5e852d6cf58dd8bb2fc6fbdffbe7d75b5e5d8a26b9b4a7cbe4ca75e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): Wscript.Shell"" ) ")
objdata_01_off00013f4c.bin rtf-objdata-decoded RTF \objdata at offset 0x13F4C 12261 bytes
SHA-256: 12289ea42203fe86d5d6e86e52672f752ead5709842d0443203b40a4917d5ece
objdata_02_off00019f5c.bin rtf-objdata-decoded RTF \objdata at offset 0x19F5C 2632 bytes
SHA-256: 82ad79f62d6dfc14694497a9a15cafc0d7d55f5ec8ce91df6ced1e7f663a3922

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