Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f731018a1b9dc756…

MALICIOUS

RTF / .DOC

32.8 KB First seen: 2023-06-08
MD5: b21f2f0fa8b26138467217186835305e SHA-1: a867a234e4e16764d07155c225e4bb8e5cd2d007 SHA-256: f731018a1b9dc756637d7eb47f4ed2932a531f86a43470cd69659c25cb78a804
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The \objupdate directive indicates that the OLE object will be activated automatically upon opening, bypassing user interaction for activation. The document body contains a lure to 'Enable editing', which is a common tactic to trick users into allowing malicious content to run. The primary attack vector appears to be exploiting the Equation Editor vulnerability to achieve arbitrary code execution.

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_off00004974.bin
3038ffcbddb85d068426e9c18623616cbd9c68ad9f71ea268488f105b1c2a2aa
rtf-objdata-decoded RTF \objdata at offset 0x4974 1809 bytes