Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d9f06802e559598c…

MALICIOUS

RTF / .DOC

35.1 KB First seen: 2023-02-09
MD5: fd448b22f135e989f1c9c69fba5911ac SHA-1: 21e38534d4dfac3ecd57bde9605106fbce13152a SHA-256: d9f06802e559598c7d075f2a0da8bcae5a7118e266687adcdaf0a0b6f15bf151
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The RTF document contains an embedded OLE object with a specific Equation Editor ProgID, triggered by an \objupdate directive. This strongly suggests an attempt to exploit a known vulnerability, likely CVE-2017-11882, to execute arbitrary code when the user enables editing. The document body contains a lure to encourage this action.

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_off0000410d.bin
f1b88d26a27a278ed335e7b3e8ece774846a28ecdfe79b8a48b9547a8b1f1d4b
rtf-objdata-decoded RTF \objdata at offset 0x410D 1837 bytes