Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d6f3694d7c009f73…

MALICIOUS

RTF / .DOC

1.79 MB First seen: 2023-03-22
MD5: eda174e3f27c80dcd19abfb5400c50d9 SHA-1: 14002d710bb0fc29a8103d3909c542e680020f63 SHA-256: d6f3694d7c009f73f53fa28d77a65eafd3ae19c9d219982a71f150c514a86584
222 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an OLE object specifically crafted to exploit the Equation Editor vulnerability (CVE-2017-11882). This exploit is designed to decode and execute a Portable Executable (PE) payload embedded within the object data. The presence of excessive hex-encoded data and the objupdate directive further indicate the malicious intent to activate and run the embedded exploit.

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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1880KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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_off00000096.bin
d9696d036cfc1f6691c3dea448d91ed8aef12a8ff7aa20de912cc1f0b46b5a56
rtf-objdata-decoded RTF \objdata at offset 0x96 940056 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.