Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c8b4d0795b49a78e…

MALICIOUS

RTF / .DOC

87.6 KB First seen: 2023-05-09
MD5: 74c488ff78cdf62fe6360c577cc26953 SHA-1: 925ad3eeb9d3cc40474f925d0495977081959995 SHA-256: c8b4d0795b49a78e0de9122265286b18ac5ccef0aa4ecae129e6f277a443e017
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1059.003 Windows Command Shell

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of `RTF_EQUATION_EDITOR` and `RTF_OBJUPDATE` heuristics strongly indicates exploitation of this vulnerability. This technique is commonly used to download and execute a second-stage payload, leading to a full system compromise.

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.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000885.bin
70333a7c2f37c67055d3e193a6b3c8af53a955990606cb41c6767e7af29a25ab
rtf-objdata-decoded RTF \objdata at offset 0x885 25258 bytes