Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f24781001f198ec7…

MALICIOUS

RTF / .DOC

34.1 KB First seen: 2023-05-08
MD5: b94ab0ff3e9e9f20e322a7571fcf041f SHA-1: 4b2cdbfb38262df6976f0ce23c8e5aa8a002e5a5 SHA-256: f24781001f198ec760cdf8805dc1fb123558d60d32e0cefbffe0a410f0519838
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The presence of \objupdate and a lure to 'Enable editing' suggests the document is designed to automatically activate the OLE object and execute a payload. The embedded object itself is the primary IOC.

Heuristics 5

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00005a4c.bin
b06683d3c2bab3aab892034d59b4687f2e602ca1b13312aae75dc9d9c1587266
rtf-objdata-decoded RTF \objdata at offset 0x5A4C 1976 bytes