Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 46b8e124c320b78d…

MALICIOUS

RTF / .DOC

1.45 MB First seen: 2023-06-09
MD5: 964a755ae41747d5bc8510c8da62d728 SHA-1: eadac7395e13b30f1e3fe4181e00fbff6093cf83 SHA-256: 46b8e124c320b78d36dff0f84c12d129ae5d2eb10ee8211d64a50077d90d0b17
222 Risk Score

Malware Insights

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

The RTF document contains OLE object data, specifically a decoded Equation Editor payload. Heuristics indicate a critical vulnerability, CVE-2017-11882, is being exploited through the Equation Editor OLE1 native payload. This suggests the document is designed to drop and execute a secondary malicious file, likely a PE executable, upon opening.

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 ~1515KB 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_off00000092.bin
1ac78b2d84f87b2722b9922282a3365b8cdc9d18a8cac3a4bd52d8ee5954a63b
rtf-objdata-decoded RTF \objdata at offset 0x92 757974 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.