Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ac3b9fe839c4df1f…

MALICIOUS

RTF / .DOC

81.6 KB First seen: 2023-02-24
MD5: d40cbef8b42672eb2398dcac363cc8c9 SHA-1: 776f6e468d2deee5546bbca2d24aa918f4cd8867 SHA-256: ac3b9fe839c4df1f74aa115a22b917e0f1bfc172cfdb686dd6564f7469531ee7
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 containing an embedded OLE object that exploits a known vulnerability in the Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic for macro-based malware. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly suggests an exploit targeting this component. The primary goal is likely to download and execute 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_off0000245a.bin
f94af6f79285bca63523acd81b8ba220187540028704516df0e71267b8f282b2
rtf-objdata-decoded RTF \objdata at offset 0x245A 1675 bytes