Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 bd0df69de7890683…

MALICIOUS

RTF / .DOC

101.3 KB First seen: 2023-01-19
MD5: 18546cb34979f64737a84dc2593d9d65 SHA-1: 37ca6fade9a5a1f9ee0941054bb05c9ca9c8f63b SHA-256: bd0df69de7890683631c530201b66700e9ab9b5fe6694bdd305ac06ed06d144c
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.005 Visual Basic T1559 Component Object Model Hijacking T1559.001 Component Object Model

The file is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The heuristic firings indicate that the document attempts to activate this object, which is a known method for arbitrary code execution. The document body contains a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The embedded object's ProgID, 'EQUAtION.3', is a key indicator of this specific exploit.

Heuristics 6

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off00004937.bin
39eb95862aa911ac3c5f4fd0a9cf931128ef6b143f86e080be83e088e07dbd48		 rtf-objdata-decoded RTF \objdata at offset 0x4937 1727 bytes

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