Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 398e913246cb5c30…

MALICIOUS

RTF / .DOC

30.6 KB First seen: 2023-01-09
MD5: 762f5008e4caf80ad0cb890ca450696d SHA-1: 06e24721f83ec88e4b01282a405d42007e01d64c SHA-256: 398e913246cb5c30a44286752661075d0e9e610ac789e5b345f46bfb716892a4
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, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The \objupdate directive further suggests that the embedded object is designed to be activated automatically. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware. While no scripts were directly extracted, the heuristics strongly suggest a malicious OLE object designed to execute 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_off0000565f.bin
ab4f4d3f674d47ff92d4806977bb2b72fc0c03f96d43445d999679f9865ee5fb
rtf-objdata-decoded RTF \objdata at offset 0x565F 1341 bytes