Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3d9859ea552a73c7…

MALICIOUS

RTF / .DOC

96.2 KB First seen: 2023-08-22
MD5: c28a737f17aea64ba40c79ee334fb81a SHA-1: 3d3bb5facc1986a87915df61f0b76301d6502574 SHA-256: 3d9859ea552a73c7d9a56c5d1f4284bb9a7bc555daeca4ea5ba4c75533364d33
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 sample is an RTF document exploiting the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics. The SE_ENABLE_LURE heuristic suggests the document body contains text designed to trick the user into enabling editing and macros. The embedded OLE object data further supports the malicious intent, 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_off0000396f.bin
3c59f0f13e0468cbafda374902d3242a69dd25d78294f762debcab317f58c2c7
rtf-objdata-decoded RTF \objdata at offset 0x396F 1525 bytes