Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 87af5e522c1f36c1…

MALICIOUS

RTF / .DOC

68.0 KB First seen: 2023-10-18
MD5: 319adda8161c6257db5b894bfe89ef74 SHA-1: 52fe66d85039b50dcc31e11a4291feccdd4ca7a8 SHA-256: 87af5e522c1f36c1f9ecb51c096145609c3fcf2e18f29b964abf520585ae1c3b
180 Risk Score

Malware Insights

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

The file is an RTF document containing OLE object data, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'click Enable editing from the yellow bar above', which is a common tactic for macro-based malware or exploit delivery. The presence of RTF_OBJAUTLINK and RTF_OBJUPDATE heuristics further indicates an attempt to automatically activate embedded objects, likely to trigger the exploit.

Heuristics 5

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 1 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000413d.bin
0cb2acb7c9695c723d3c555e54ddc2582a3a8351b99534fa18fbc85880c8ff13
rtf-objdata-decoded RTF \objdata at offset 0x413D 1579 bytes