Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 935e0eab17f7949a…

MALICIOUS

RTF / .DOC

60.1 KB First seen: 2023-08-09
MD5: c39c61ddaa665c4de18b419c3ca106bc SHA-1: dbab5b714433ae259da4a3e17d6de6d3d8765364 SHA-256: 935e0eab17f7949a0b1b7af4f68cbde5361e82330a201f5ccded2fb2b45c50fc
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that exploits the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR heuristic. It also contains an OLE object and uses \objupdate to force activation, suggesting it's designed to execute a payload. The document body provides a lure related to financial audits, instructing the user to 'Enable editing', which is a common tactic for macro-based malware delivery.

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_off00003583.bin
e3320ce3cb1aca4f64ac465a44d536364af8efc499ad292d616516da05769b09
rtf-objdata-decoded RTF \objdata at offset 0x3583 1348 bytes