Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 99e5ce61c8f39b55…

MALICIOUS

RTF / .DOC

312.1 KB
MD5: 53433c4fe8031cb42483317302ec3929 SHA-1: 5f795dc324b8b29924768320d4dba501500ab197 SHA-256: 99e5ce61c8f39b55126f771de2cc412a3749341e3ec5a580bcdbfea5df837019
122 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The ".objdata" and ".objupdate" heuristics indicate that the embedded object is designed to be activated, likely to execute a secondary payload. The extracted artifact "objdata_00_off0000174c.bin" is the decoded content of this embedded object.

Heuristics 4

  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \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.
  • 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_off0000174c.bin
ffddf6cff819203fdbd798e68cb2d89c8c62c63140a08dd4b4fd81e34afb3d21
rtf-objdata-decoded RTF \objdata at offset 0x174C 156769 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.