Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6263c79f4de4b611…

MALICIOUS

RTF / .DOC

1.37 MB First seen: 2023-02-06
MD5: ba094f5a630a1f3ded9f712602998667 SHA-1: 0cf896384360c5e6ff16924354309a8d504b4b26 SHA-256: 6263c79f4de4b611caa5ded224b8954117986e5e7f3c5e4d03bbf238f074d50f
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 allows for the execution of arbitrary code when the OLE object is activated. The presence of a PE file within the decoded object data strongly suggests that a malicious payload is being delivered and executed.

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 ~1440KB 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_off00000072.bin
7803fbd0e9c70563dbab0e9d91091aace840dc0f59dded2e7283ca87b7848fc7
rtf-objdata-decoded RTF \objdata at offset 0x72 720231 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.