Malicious RTF — malware analysis report

Static analysis result for SHA-256 a5ba37dd5d68d296…

MALICIOUS

RTF

39.0 KB First seen: 2023-07-14
MD5: 02b0d5b5fa2e4af193c0368535f932b6 SHA-1: cad44b0b545abcc6cc89498d3776899c5f4d5b4d SHA-256: a5ba37dd5d68d2963a71a1ac45cca1a73576608ced1452c49edf92dc9b577f1f
140 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a specific Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The \objupdate directive suggests that the object will be activated automatically upon opening, and the 'SE_ENABLE_LURE' heuristic confirms the presence of a prompt to enable editing, a common social engineering tactic. This combination strongly suggests the document is designed to exploit the Equation Editor vulnerability to deliver a secondary 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_off00005a25.bin
1ea35dea4ab517496d0b054b748edb3987e5e5bb0abebf9d2fcec5688fda9133
rtf-objdata-decoded RTF \objdata at offset 0x5A25 1356 bytes