Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6133b893d7e58fa3…

MALICIOUS

RTF / .DOC

44.8 KB First seen: 2022-12-23
MD5: 7fa890b8545287e23588f5467dbd8a9c SHA-1: 19a3ea3af5638a7278f85eb0679700f1c83f5511 SHA-256: 6133b893d7e58fa37e905414f57f42e5bd8ee54f3a470f4dae6f65c16e5134ca
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of \objupdate and SE_ENABLE_LURE heuristics indicates a lure to activate the object. This technique is commonly used to exploit the Equation Editor vulnerability to execute arbitrary code, likely leading to the download and execution of a secondary 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_off0000850b.bin
38dff27cb12392e4598448b5d92579e0d6fb75979284964f86789e2338584758
rtf-objdata-decoded RTF \objdata at offset 0x850B 1438 bytes