Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b7def2b5917718c3…

MALICIOUS

RTF / .DOC

5.4 KB First seen: 2022-10-20
MD5: dcf85363635d552818cc926efe0668c3 SHA-1: ab5a48a62dbe8495df1f8eb2186309a3252e6bf8 SHA-256: b7def2b5917718c3d8daadd3e4a6502e7223dc846d0032b5aa32820c5413b821
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.002 Component Object Model and Distributed Component Object Model

The RTF document contains an embedded OLE object that is automatically linked and updated, triggering activation. Heuristics indicate this object is related to CVE-2017-11882, specifically targeting the Equation Editor component (eqUaTioN.3). This exploit allows for the execution of arbitrary code upon opening the document.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000076.bin
309e0d5bedb53ee920becef2f754143e23fc50cc72526d6e85e7e6bcad28631b		 rtf-objdata-decoded RTF \objdata at offset 0x76 2487 bytes

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