Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 30b747869e94c1b8…

MALICIOUS

RTF / .DOC

1.67 MB First seen: 2023-09-06
MD5: 960b4b9f99917d2cb5c1e0a3d61bb5e9 SHA-1: 8c1a58de2ac6304c0a95c3b532f49167eaabce25 SHA-256: 30b747869e94c1b89e36a0a977e8983c5c02d16df894e4edcc578e63a929bdc6
222 Risk Score

Malware Insights

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

The RTF document contains an OLE object with decoded Equation Editor payload, strongly indicating exploitation of CVE-2017-11882. The presence of a PE file within the OLE object suggests it's a downloader or dropper for a secondary malicious payload. The excessive hex data and OLE object updates further support the malicious intent.

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 ~1746KB 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_off0000008c.bin
c9a8c326a99c5a3e81b71977e33dca01143c4329f9b48182e24513cf13b51b5b
rtf-objdata-decoded RTF \objdata at offset 0x8C 873040 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.