Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 139da9e6232350a5…

MALICIOUS

RTF / .DOC

107.0 KB
MD5: 8b877a90378d609b0a2fdb4b9f7edbe8 SHA-1: 6ce9c47cd534209b19e42335cf17b3755539c480 SHA-256: 139da9e6232350a5aafd668b16238483ca077a9bbbf747d588bfd0b449ee1644
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains multiple indicators of exploiting the Equation Editor vulnerability, including RTF_EQUATION_EDITOR, RTF_OBJAUTLINK, and RTF_OBJUPDATE heuristics. This strongly suggests the file is designed to execute arbitrary code, likely by downloading and running a secondary payload. The presence of OLE object data further supports this conclusion.

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_off0000177c.bin
b7dbffbd855a436006d68b89b021b164d8748efaaa6952367b249456fc711d01
rtf-objdata-decoded RTF \objdata at offset 0x177C 2224 bytes