Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f0edb21a9b43fc99…

MALICIOUS

RTF / .DOC

190.2 KB
MD5: 39180a5501ab20ff74dedeaadec0e5fe SHA-1: d44336e618e21fabc8c5fabf6e3281d3d3b1587b SHA-256: f0edb21a9b43fc99c858009b07b27fcc19c80d20e1f1e4667f67b00c869ec800
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains embedded OLE objects, specifically triggering the Equation Editor. Heuristics indicate the exploitation of CVE-2017-11882, a critical vulnerability in Microsoft Equation Editor, which allows for arbitrary code execution. The presence of ".objupdate" and "RTF_EQUATION_EDITOR" firings strongly suggest this exploit is being leveraged for initial execution.

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.
  • \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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001f42.bin
da2d3521540b474997b0ebd5c4921aa78babe43b20411f3686cd8f9b69e18021		 rtf-objdata-decoded RTF \objdata at offset 0x1F42 1816 bytes

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