Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b9c28b16a14774b6…

MALICIOUS

RTF / .DOC

804.6 KB
MD5: 5d4a2b9d8e7eae35a742fc9d9a247811 SHA-1: 9c9a041e78bf6c2797ecb64aeed47f63f34d8255 SHA-256: b9c28b16a14774b6e602a5391ab968f267a08c2547deb6270df06381223f9873
222 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1559.001 Component Object Model T1059.001 PowerShell

The RTF file contains an OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability is known to be used for delivering second-stage payloads. The heuristic firings strongly indicate the exploitation of this CVE, leading to the decoding of a PE file. No document body text was available for analysis, but the technical indicators are sufficient to determine the attack vector.

Heuristics 6

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • 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.
  • 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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001ce4.bin
5ade16f1c41952b66e38b1417b2bc88146621cf7e0ad08c48ae94ebf3b6fa4bf
rtf-objdata-decoded RTF \objdata at offset 0x1CE4 408137 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.