Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3a4391dc38bcc93f…

MALICIOUS

RTF / .DOC

46.4 KB First seen: 2023-02-21
MD5: e55223373648601b9a1cb28056c3af55 SHA-1: 6b37677c069a8e3cb241f62106a3a15567034d3b SHA-256: 3a4391dc38bcc93f4b20fd1f34c00c0eab896290e38bd7dd7a2e02036c70a1fb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1059.005 Visual Basic

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware droppers. The presence of ".objupdate" further suggests an attempt to automatically activate the embedded object, likely to trigger the exploit and download 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_off0000585b.bin
90081533a053ca02398ed0e72d8de13f167a94eafbbde8a7410a821cfc04895f
rtf-objdata-decoded RTF \objdata at offset 0x585B 1888 bytes