Malicious RTF — malware analysis report

Static analysis result for SHA-256 6b7fe61a84cc8be5…

MALICIOUS

RTF

58.4 KB First seen: 2023-08-03
MD5: 2bb765bd15e09b84698157a6f3e103a6 SHA-1: 7fada09da43d8816048c1052590c3e7e0c6f7651 SHA-256: 6b7fe61a84cc8be5f01cd3eb0952f7ce426ba259998c57a49540ddecaa8b8576
180 Risk Score

Malware Insights

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

The file is an RTF document exploiting the Equation Editor vulnerability. Heuristics indicate the presence of OLE objects and an attempt to automatically update them, suggesting the execution of embedded malicious code. The document body contains a lure to enable editing, which is a common tactic for macro-based malware.

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_off0000387f.bin
57ab040a3c4de227f9184080c67e2a46bfb21c5da771036e1ce4ea85522042bb
rtf-objdata-decoded RTF \objdata at offset 0x387F 1903 bytes