Malicious RTF — malware analysis report

Static analysis result for SHA-256 4d1bab86d362aa6d…

MALICIOUS

RTF

1.16 MB First seen: 2019-05-16
MD5: e0df7b779e3eb6dbf94eb92b305cdec2 SHA-1: 10ad45ae3564d663b6efce0e121e836bc6d0744b SHA-256: 4d1bab86d362aa6d805dbcc347bcb7545091c4cdf97342e30c9ad3636ce8b522
464 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of exploitation for CVE-2017-8570, including the presence of a composite moniker and Equation Editor CLSID. The ".bin" artifact extracted from the objdata section, detected by ClamAV as Win.Packed.Jaik-7334710-0, is likely the second-stage payload. The file's structure suggests it was delivered as a spearphishing attachment.

Heuristics 11

  • 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.Packed.Jaik-7334710-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Packed.Jaik-7334710-0
  • 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1025KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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://www.usertrust.com1 In RTF body
    • http://ocsp.usertrust.com0In RTF body
    • http://crl.usertrust.com/UTN-USERFirst-Object.crl05In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordml}}\paperw12240\paperh15840\margl1440\margr1440\margt1440\margb1440\gutter0\ltrsectIn 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 512692 bytes
SHA-256: 1fcb73f36838531a09d977662e8a5976c0c79cae5ffeb0bdcc1697f447a1d53c
Detection
ClamAV: Win.Packed.Jaik-7334710-0
Obfuscation or payload: likely
Carved artifact entropy is 7.71, consistent with packed or encrypted content.
objdata_01_off00112bff.bin rtf-objdata-decoded RTF \objdata at offset 0x112BFF 35423 bytes
SHA-256: 22595f0f02eb7791c0172c6747914ab8895a07b916e3b409f49266a03bac74c4
objdata_02_off001240f5.bin rtf-objdata-decoded RTF \objdata at offset 0x1240F5 382 bytes
SHA-256: 9d6fa4be1a4a694cfee89268078c9efc8705b1a473fbb09a37ceb2d45104e44b
objdata_03_off0012442d.bin rtf-objdata-decoded RTF \objdata at offset 0x12442D 789 bytes
SHA-256: 8ab026a3e66d94feae5647d5ac6558412271b58006835755f301bcce43b1e52a
objdata_04_off00124ad5.bin rtf-objdata-decoded RTF \objdata at offset 0x124AD5 2633 bytes
SHA-256: 1feb5f150bb35566d1a01fc59a357dc0ea34bc7498e0ec99bd939f6f848044b0
objdata_05_off00125ffd.bin rtf-objdata-decoded RTF \objdata at offset 0x125FFD 4679 bytes
SHA-256: 6bb172535cccd16de71bca846e2bb6df177c56b3a545d6e6314435eabf5d2217

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