Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1256ae8e8b9e0a3a…

MALICIOUS

RTF / .DOC

642.4 KB
MD5: e15b6be79b819eea3f6f52d7a5a209a1 SHA-1: ef521215f61121ab8a9ea2672a4350d8860cc79a SHA-256: 1256ae8e8b9e0a3aaa68b4d883f404de4cb55208aabef010c04231b1a1e11edf
182 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data, specifically related to Microsoft Equation Editor. Heuristics indicate a critical vulnerability, CVE-2017-11882, which is known to be exploited for client execution. The presence of a high-entropy carved artifact suggests the embedded object is a packed or encrypted payload, likely a second-stage executable.

Heuristics 5

  • 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.
  • 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_off00000042.bin
c87af8ded6a2b399ffbf79761d6cc02e0c19505956c8d0ac845b6271c5d994ec
rtf-objdata-decoded RTF \objdata at offset 0x42 328770 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.