Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 36047edee76991ab…

MALICIOUS

RTF / .DOC

37.3 KB First seen: 2023-02-08
MD5: 285a89c80adb7aaa99bcc5520db5d157 SHA-1: 24dc77157ef3917920b4b97fdd9ed1ab25ee110c SHA-256: 36047edee76991abf7488230ee76595be53542c3c2f994f1256f00ea5e56ece6
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (RTF_EQUATION_EDITOR). The document also contains a lure instructing the user to 'Enable editing' to view its content, which triggers the OLE object activation ( TF_OBJUPDATE). This combination strongly suggests a malicious document designed to exploit a known vulnerability upon user interaction.

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_off00005be9.bin
481fef81d57a86a95a524814cce2f2b2c2564907ea48e5b01370d9a39a900e6b
rtf-objdata-decoded RTF \objdata at offset 0x5BE9 1415 bytes