Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 27889ccfdf51ef05…

MALICIOUS

RTF / .DOC

20.4 KB First seen: 2023-03-13
MD5: f74b00debddbcbba75715a8f92456cf7 SHA-1: 66ddbb6e4454dc7f792dbbe9074cb3c0567a202e SHA-256: 27889ccfdf51ef05c2a60a9711ed22138be0f5d0b4a8d540e760051557bcd2a6
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 that leverages an Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics. The SE_ENABLE_LURE heuristic confirms the presence of a lure to enable editing, which is a common tactic for macro-based malware. The embedded OLE object data suggests the execution of 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_off0000329c.bin
4230f104c55a4249c1af29182fbfd87f1e7fee561ba12fbabf1801339231a62f
rtf-objdata-decoded RTF \objdata at offset 0x329C 1773 bytes