Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 9c29357e88a53d1c…

MALICIOUS

RTF / .DOC

23.3 KB
MD5: c83bbd8adb1a53522010b8c068828664 SHA-1: 2ec0c7008b61fe63fd9c838279e6509b1561bff5 SHA-256: 9c29357e88a53d1cad99664a4c1ae0415a73e7bddbec85201564e5e4fc5ebbfe
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that contains embedded OLE object data, specifically a decoded Equation Editor payload. The \objupdate directive forces the activation of this OLE object, which is known to be a vector for exploiting vulnerabilities like CVE-2017-11882. The decoded object is a PE file, indicating it's likely a secondary stage payload. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly suggests exploitation of the Equation Editor vulnerability to achieve code execution.

Heuristics 3

  • Decoded Equation Editor payload + PE critical RTF_EQUATION_EDITOR
    RTF decodes to an Equation Editor ProgID adjacent to OLE activation and the same decoded object stream contains embedded PE bytes. This matches the Equation Editor exploit surface used by CVE-2017-11882 / CVE-2018-0802 documents, while requiring payload evidence to avoid flagging benign Equation references.
  • \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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001a72.bin
3fc3185753d4b5d931e3c4910b942f959214eb1287e355863e83a779de57f6f0
rtf-objdata-decoded RTF \objdata at offset 0x1A72 2154 bytes