Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a62389267d9b435e…

MALICIOUS

RTF / .DOC

40.5 KB First seen: 2023-07-12
MD5: 9efc5bf89911efa2f7c3e6eb52313b24 SHA-1: 565327d2fd9e07e75546eb84bef5427dd1d19350 SHA-256: a62389267d9b435e7b9bad508c5a20c9516b3946390763a1d1db3abf93743dd1
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 PowerShell

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common technique to bypass macro security settings and trigger the exploit. The presence of RTF_OBJDATA, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly indicates this attack vector.

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_off000054ad.bin
b2f0af7c6edadd7ee3538da573363601dfca5542aa63cd6fa4c8a033cc13ba7a
rtf-objdata-decoded RTF \objdata at offset 0x54AD 1591 bytes