Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5d4660252f2bd917…

MALICIOUS

RTF / .DOC

30.0 KB First seen: 2023-04-11
MD5: 6a5f45b15eb2ca3a5e924048cc8e24c0 SHA-1: 31cdc14336e718427478052d13f26d6d431b1001 SHA-256: 5d4660252f2bd91774a064553be39c605713e6d4da8d9a1a0a3eccdd377cefdd
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 PowerShell

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of \objupdate and a lure to 'Enable editing' strongly suggests an attempt to exploit this vulnerability for initial execution. The document body itself appears to be benign academic content, indicating the lure is purely to facilitate the exploit.

Heuristics 4

  • 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.
  • \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_off00004331.bin
5e94f49d2fdd03cfab4441754cce344edd7c136410e993b38b0e00d1e0ae90c4
rtf-objdata-decoded RTF \objdata at offset 0x4331 1875 bytes