Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a58ad0d4b2f1aed5…

MALICIOUS

RTF / .DOC

4.0 KB First seen: 2021-09-17
MD5: 70d7df299d386403bc4a1c604033b05d SHA-1: fb73830d1cedc60766dd8297ea28326c3d43edfb SHA-256: a58ad0d4b2f1aed541a01fe1c4198cc713da4193faab575058a843374721c11d
160 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects, specifically targeting the Equation Editor vulnerability. The presence of ".objdata" sections and the "RTF_EQUATION_EDITOR" heuristic strongly indicate an exploit attempt. The "RTF_OBJUPDATE" heuristic suggests that the embedded object is designed to be activated automatically, likely leading to the execution of a malicious payload.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000a9.bin
7d0a921a5fe56be586d1ddfdd86ef7f4f887bc5908cc0bc47d178952a188b5cc
rtf-objdata-decoded RTF \objdata at offset 0xA9 1841 bytes