Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 52fd58de6b48304d…

MALICIOUS

RTF / .DOC

1.31 MB First seen: 2023-04-19
MD5: ee32b44268337568ad4d404096619a39 SHA-1: 6f14e95eb8a8cf9bf8caaae15eaa60166ff1c77b SHA-256: 52fd58de6b48304d5bd6a04bff058448a6bcf98833f437e5b931cf1ab748b686
222 Risk Score

Malware Insights

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

The RTF document contains a decoded Equation Editor payload and is related to CVE-2017-11882, indicating exploitation of this vulnerability. The presence of OLE object data and excessive hex data suggests the embedding of a malicious executable. The document likely serves as a lure to trigger the exploit when opened.

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 ~1376KB 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_off00000091.bin
3b791dbd2696da43ac4d338dccebeb6a12b369b6d3027441dc7541fb274d1b63
rtf-objdata-decoded RTF \objdata at offset 0x91 688519 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.