Malicious RTF — malware analysis report

Static analysis result for SHA-256 c1a5cbff787eef2c…

MALICIOUS

RTF

671.1 KB First seen: 2020-05-14
MD5: c26677ad0eae114d1e9efb17cab69790 SHA-1: 6334506444071f73389402a8d0384382d47d9fa7 SHA-256: c1a5cbff787eef2c6c1f3a7242d884945f3b660b7db7e0f971a47d866b64adf2
202 Risk Score

Heuristics 6

  • Decoded Equation Editor payload + PE critical CVE likely 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.
  • 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.
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off00002040.bin rtf-objdata-decoded RTF \objdata at offset 0x2040 339454 bytes
SHA-256: c99204be58c11f539940405fbe3a7ce6118b42435a84d8ae28b9c3f8d42f7c67
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.