Malicious RTF — malware analysis report

Static analysis result for SHA-256 cf0c78efce38f415…

MALICIOUS

RTF

3.38 MB Created: 2024-04-03 08:46:00 First seen: 2025-05-26
MD5: 043260c617c1512cf252110f3b4ca0b2 SHA-1: 40ed3c0b32ae78ab436aeeed7d707d9217c9ef13 SHA-256: cf0c78efce38f415a3bd391725d200a301b341d46e1e57a00038e197d43ccb69
322 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains multiple indicators of exploitation, including RTF_EQUATION_EDITOR, CVE_2017_11882_ACTIVATION_RELATED, and RTF_MZ_HEX. These heuristics strongly suggest that the embedded OLE object, specifically related to Equation Editor, is designed to execute a malicious PE file. The large amount of hex-encoded data within the object further supports the presence of a hidden payload.

Heuristics 9

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • 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 ~1344KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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://ocsp.verisign.com0
    • http://schemas.microsoft.com/office/word/2003/wordml
    • https://www.verisign.com/rpa
    • http://csc3-2010-crl.verisign.com/CSC3-2010.crl0D
    • https://www.verisign.com/rpa0
    • http://csc3-2010-aia.verisign.com/CSC3-2010.cer0
    • https://www.verisign.com/cps0*
    • http://logo.verisign.com/vslogo.gif04
    • http://crl.verisign.com/pca3-g5.crl04
    • https://www.globalsign.com/repository/0
    • http://ocsp.globalsign.com/ca/gstsacasha384g40C
    • http://secure.globalsign.com/cacert/gstsacasha384g4.crt0
    • http://crl.globalsign.com/ca/gstsacasha384g4.crl0
    • http://ocsp2.globalsign.com/rootr606
    • http://crl.globalsign.com/root-r6.crl0G

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003a12.bin
4135d7c3d8895dfd4fa6e9a2e97a9232a976ce6330ac552da638a80e754c97b2		 rtf-objdata-decoded RTF \objdata at offset 0x3A12 685290 bytes
objdata_01_off0015dc18.bin
31e3bdb4635082b6f5401bd7688a1baf90019932fe37de5dee9246f0964b7ef4		 rtf-objdata-decoded RTF \objdata at offset 0x15DC18 584266 bytes

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