Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 154ad3c86d2a3c4d…

MALICIOUS

RTF / .DOC

1.75 MB First seen: 2023-02-28
MD5: ecf63933f952c0681497cb895e703041 SHA-1: 73181418d4aaaa319a37b8dbc8a53daf33bef566 SHA-256: 154ad3c86d2a3c4dc332a7a130ef5c437735530d8c511aa85a1bb13dbc6fc45d
222 Risk Score

Malware Insights

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

The RTF document contains an OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability is known to be used for delivering arbitrary executable code. The presence of a decoded PE file within the OLE object strongly suggests that the document is a dropper for a malicious payload.

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 ~1831KB 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_off0000007e.bin
160278ae8b713460039b750d4215541b542b66c48ce5f7ef1bb62007481b1df4
rtf-objdata-decoded RTF \objdata at offset 0x7E 916159 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.