Malicious RTF — malware analysis report

Static analysis result for SHA-256 7d4a1c05f377343f…

MALICIOUS

RTF

2.75 MB First seen: 2022-08-08
MD5: 26111b2647fc8b1e3e123e825f716b94 SHA-1: 131907f569a2774c1800430ccf052896dc685ec0 SHA-256: 7d4a1c05f377343f063e0b265fc85f928b59f0cd88914f2b2715c4a25c734838
382 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects, specifically exploiting CVE-2017-11882 through the Equation Editor. This exploit is designed to drop and execute a secondary payload, as indicated by the presence of hex-encoded PE headers and ClamAV's detection signature 'Rtf.Dropper.Agent-9965975-1'. The document body appears to be malformed or obfuscated script content, further supporting the dropper functionality.

Heuristics 10

  • 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
  • ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
  • \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 ~1897KB 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
  • 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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001291.bin
86faedcdbc551928f09bd5360a21854ee823dd5dc273ac5832eea3cd3316e249
rtf-objdata-decoded RTF \objdata at offset 0x1291 959235 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.72, consistent with packed or encrypted content.
objdata_01_off001df7c1.bin
ffd8c2482cc64da211bcb7ca32c7331bf3796ad5ca2159f697062f334496c915
rtf-objdata-decoded RTF \objdata at offset 0x1DF7C1 187349 bytes