Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 25c709ee5f5191d7…

MALICIOUS

RTF / .DOC

20.2 KB First seen: 2023-03-15
MD5: ba4b28802911de69ab9952f745039bf4 SHA-1: bef2f600358a8372d479da3b5429f77db5cf8e49 SHA-256: 25c709ee5f5191d7a6c8df5d6e8098163eb881c2cee92ca9c4322a5705b443d4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that leverages OLE object data and specifically targets the Equation Editor vulnerability. The document body contains a lure explaining why users might need to enable editing, which is a common tactic for macro-based malware. The presence of RTF_OBJDATA and RTF_OBJUPDATE heuristics further indicates the exploitation of OLE objects to deliver a 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.
  • \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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000029d9.bin
16f51b29356cb4c72395629e041be48a4d599458fcb146b20e13ff3629a9dfba
rtf-objdata-decoded RTF \objdata at offset 0x29D9 2192 bytes