Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 164f271412681414…

MALICIOUS

RTF / .DOC

107.0 KB First seen: 2023-10-24
MD5: a88cdb8b15c191da58017f1cecb2bb6c SHA-1: ee981d84fdc3c48aa36895f9678f3436f6a36187 SHA-256: 164f2714126814149fbed4dc3ae5b82fdf8ba50ff6e01011b110103147bd3b38
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits a known vulnerability in the Microsoft Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic to bypass macro security settings. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly indicates an exploit targeting this component.

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_off0000403c.bin
d6d1b8e5e560f29a804e304ff895a4746ec219544d07e1e0ba47ffd58116f651
rtf-objdata-decoded RTF \objdata at offset 0x403C 1744 bytes