Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 13d4fdf58e85297b…

MALICIOUS

RTF / .DOC

39.3 KB First seen: 2023-02-20
MD5: 90668d2907c438bd0eb4a7047510d13d SHA-1: be3fb76c3c261c56c87e7df2560c941b13173fa8 SHA-256: 13d4fdf58e85297bb41a22e87d15a2ed4040e65ed321bab04acbb335a9c58200
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object, specifically identified as an Equation Editor exploit. The presence of \objupdate indicates that the OLE object is designed to be activated automatically upon opening or enabling editing. The document body, disguised as an academic assignment, serves as a lure to trick the user into enabling content, which would trigger the exploit.

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_off00004953.bin
ba1522824f369bffc2aa9d5e7384ce257672a477aad1bcd122cf1256a5ea00fc
rtf-objdata-decoded RTF \objdata at offset 0x4953 1660 bytes