Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 29d5bd8a4fea152b…

MALICIOUS

RTF / .DOC

41.7 KB First seen: 2023-02-07
MD5: 59680eccd688d64167a1bfc0fbe26903 SHA-1: 75667c6c9ba92fc48838b7f1ae3a667acc83a09d SHA-256: 29d5bd8a4fea152b457fdfedbe44b9cbce7d4ea5fe0c336310b4df15744dba4c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic for macro-based malware delivery. The presence of `RTF_EQUATION_EDITOR` and `RTF_OBJUPDATE` heuristics strongly suggests exploitation of a known Microsoft Office vulnerability to execute arbitrary code.

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_off00005674.bin
37310b7c9088f156e513dabbb11b60b1accdd45150696518a8fac9fce4081367
rtf-objdata-decoded RTF \objdata at offset 0x5674 1924 bytes