Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ebb3f203a22c8abf…

MALICIOUS

RTF / .DOC

31.1 KB First seen: 2023-02-23
MD5: 2fbdba172f5390b41212ea5430d00844 SHA-1: 4adcfb4fc91310c258afeec217fac70a976d42d8 SHA-256: ebb3f203a22c8abfbda5d25a2390f86b4d57a5367e83a245d14dd4ef52bc9773
140 Risk Score

Malware Insights

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

The file is an RTF document containing an embedded OLE object that exploits a vulnerability in the Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic to bypass security measures. The presence of RTF_OBJDATA, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly indicates an attempt to exploit the Equation Editor vulnerability. The SE_ENABLE_LURE heuristic further supports the social engineering aspect of this attack.

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_off0000348a.bin
3dc51a80c61c8491aca4dc4b208f7abf0de9ddcd6df93eac3759595733a4ed60
rtf-objdata-decoded RTF \objdata at offset 0x348A 1346 bytes