Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8b2a1b1a5f3ef787…

MALICIOUS

RTF / .DOC

1.26 MB
MD5: f643ad0869e312f403fb24393a7edec3 SHA-1: ac4884060d8da9a84c80fcb24384d1042e52e91b SHA-256: 8b2a1b1a5f3ef787cfa70e33d56111f2318162bec5eb699f7371b19b7e38ee29
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1027 Obfuscated Files or Information

The RTF file contains embedded OLE objects, specifically related to the Equation Editor, which strongly indicates exploitation of CVE-2017-11882. The presence of a large, high-entropy OLE object suggests it is used to hide a second-stage payload. No document body text or scripts were extracted, making the specific nature of the payload and its ultimate goal unknown.

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.
  • 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1322KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \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_off000000b5.bin
ad17ef4ec7d70598ac174d91a6ecafbd12438fe2098bed0aabb6ed2df7063560
rtf-objdata-decoded RTF \objdata at offset 0xB5 661483 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.