Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 31f6282f5f8f27de…

MALICIOUS

RTF / .DOC

97.2 KB First seen: 2023-01-19
MD5: ec00d4c591d7ed76ef42f5d453762313 SHA-1: 194db437571fe29becb085068788fa1b36d18873 SHA-256: 31f6282f5f8f27dea62297c7f00a2d89dec8cadd84190224755797d3e4478226
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 that contains an embedded OLE object with a specific Equation Editor ProgID, triggering critical heuristics for RTF_EQUATION_EDITOR and RTF_OBJUPDATE. The SE_ENABLE_LURE heuristic indicates the document likely contains instructions to enable content, a common tactic for macro-based malware. The presence of these indicators strongly suggests an exploit targeting the Equation Editor vulnerability to achieve code execution, likely for a downloader or droppper.

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_off00008c59.bin
d5a063d72d4b803ed960595d166f4e76a2f9129cfa2a231d0b952ea322e4e773
rtf-objdata-decoded RTF \objdata at offset 0x8C59 1322 bytes