Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5b091bdb563c85af…

MALICIOUS

RTF / .DOC

364.7 KB
MD5: 9384f8aea4ee900a62534047907f6da4 SHA-1: 0f6acbc56f7371f2b8b7050b9ddb1067752aa892 SHA-256: 5b091bdb563c85af8a85a3ed4067edf4e44eb87193c429d51a5cf13600139ee5
202 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for the execution of arbitrary code, which in this case is a PE file. The embedded object's class name is 'eqUatioN.3', directly indicating the use of the vulnerable Equation Editor component.

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.
  • \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_off00000043.bin
6ec6c4ce551ba70f62d8dc77be7e432c25191b22a66b7af20c33f1447758728d
rtf-objdata-decoded RTF \objdata at offset 0x43 186624 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.