Malicious RTF — malware analysis report

Static analysis result for SHA-256 6c8cbe9aa83aa0a4…

MALICIOUS

RTF

3.3 KB First seen: 2022-12-05
MD5: efe3b23b80f8c3e55b9586034492cabc SHA-1: 82bd085b8521e9f3454a3875c4f9506305ab5d46 SHA-256: 6c8cbe9aa83aa0a443e456f0c24e0868ae91485dd88798d1094d8bc295c5e20d
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). The heuristic firings indicate that the object is obfuscated and designed to activate, leading to arbitrary code execution. No document body or script content was available for further analysis, but the exploit itself is a strong indicator of malicious intent.

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 1 \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_off00000071.bin
1a23181c7642e62fa56f3f76b804d722d28545e2a9e815d917f496cac6bd7c64		 rtf-objdata-decoded RTF \objdata at offset 0x71 1579 bytes

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