Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fa14f35545ebd1c4…

MALICIOUS

RTF / .DOC

27.9 KB First seen: 2022-11-15
MD5: 9f5c9804ff3fd5c0f448f9eb2747c22b SHA-1: d842b4b78d0675154304327e92a699416689013a SHA-256: fa14f35545ebd1c401da5cbca14e5a0aee7eae131265066f30460dd17ed83695
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious Link T1059.005 Command and Scripting Interpreter: Visual Basic

The RTF document contains an OLE object with a split Equation Editor ProgID, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The presence of \objupdate further suggests that the OLE object is designed to be activated automatically. The document body includes a lure instructing the user to 'Enable editing', a common tactic to bypass security measures and trigger the exploit. The primary goal is likely to download and execute a second-stage 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_off0000531c.bin
a8c38e17b2daf78dc588aeb9449e024bba4a59cc683858333eef69b2a6d81b6a
rtf-objdata-decoded RTF \objdata at offset 0x531C 1611 bytes