Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f617b1faa3fe8771…

MALICIOUS

RTF / .DOC

51.5 KB First seen: 2023-09-04
MD5: d179672a734bb48b3eb09938998e415d SHA-1: 61d58438fe0cdabcc8b7b533e3e8a052f21505e3 SHA-256: f617b1faa3fe8771b6bf58210d75b226aae564bc9f3171b1111ab119f71213ff
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

The file is an RTF document that exploits the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics. The SE_ENABLE_LURE heuristic and the document body content suggest a social engineering tactic to trick the user into enabling editing and potentially macros. This is a common delivery mechanism for malware that downloads and executes a second-stage 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_off00002af6.bin
0a877290e7eb3369d0154ea5fe4c18896d1ceb46dae6940dad7ca7fe35800466
rtf-objdata-decoded RTF \objdata at offset 0x2AF6 1897 bytes