Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fa290a4e9ab3396e…

MALICIOUS

RTF / .DOC

23.7 KB First seen: 2022-12-15
MD5: e18a0fe25d3f9a046a36496c5182beab SHA-1: 572d44574aca52887d3e9d269cc8487bb2baaaab SHA-256: fa290a4e9ab3396e4904a6a038798a1218038ff0ff428014076d6e6e0eaa5c9f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability. The document body contains a lure instructing the user to enable editing, which is a common technique for malware droppers. The presence of the Equation Editor exploit and the lure strongly suggests this document is designed to deliver a malicious 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_off000045ce.bin
5c2c0ae29af1287e57562dc6debd82a7316c31504a7a7612198ee2b09e4c95b4
rtf-objdata-decoded RTF \objdata at offset 0x45CE 1812 bytes