Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0a541cc53dbb9a52…

MALICIOUS

RTF / .DOC

27.5 KB First seen: 2023-03-23
MD5: 5b0f700c827197f3dab5296745669ed9 SHA-1: 0965e9fb1424ef4e229abb5b4ae87721b8433d70 SHA-256: 0a541cc53dbb9a5251a44ceab6fa9e26b160f5e36fd9640dd096dba446dbe155
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 PowerShell T1204.002 User Execution: Malicious File

The file is an RTF document that contains an OLE object and specifically targets the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic for macro-based malware droppers. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly suggests exploitation of this component to achieve initial execution, likely leading to the download of a secondary payload.

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_off000049a5.bin
0f8bc2907873e87a0b7f273d7a46a1a019d82760842852714d4445b28ac4fe74
rtf-objdata-decoded RTF \objdata at offset 0x49A5 1429 bytes