Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 16b79eac277c366d…

MALICIOUS

RTF / .DOC

4.0 KB First seen: 2022-06-03
MD5: be8a663c99f3d5650f167af3e9f91c64 SHA-1: 00bbe5fb814f9a0df361ac370380699e8b4e8bb1 SHA-256: 16b79eac277c366d17edaabc0923d70fda08b90a108157dbd3035d3f8487cb68
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains embedded OLE object data and specifically triggers \objupdate, indicating an attempt to activate an embedded OLE object. The critical heuristic firing for RTF_EQUATION_EDITOR strongly suggests exploitation of a vulnerability within the Microsoft Equation Editor component. This is a common method for delivering malicious payloads via spearphishing attachments.

Heuristics 3

  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000069.bin
d8b8c13a876b4d55b3d91cf4e79954d65d5d4843f318ae590d661a0206ab082e
rtf-objdata-decoded RTF \objdata at offset 0x69 1686 bytes