Malicious RTF — malware analysis report

Static analysis result for SHA-256 d4e45a795485d3ec…

MALICIOUS

RTF

3.0 KB First seen: 2022-11-29
MD5: 27e2ff67ffb57eda8cc005a0b45e5229 SHA-1: 045992922c8618aec535aae5f63077c608b03f7b SHA-256: d4e45a795485d3ec64924ee0e17501cefde072b4fb6028fbf65ab1277ce57097
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains an embedded OLE object with an obfuscated Equation Editor ProgID, strongly indicating exploitation of CVE-2017-11882. The presence of ".objupdate" and ".objautlink" directives further confirms that the embedded object is designed to be automatically activated upon opening the document, leading to arbitrary code execution. No scripts were extracted, and the document body contained only numerical data, suggesting the exploit is self-contained within the OLE object.

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_off00000081.bin
0858defd9be723ebe4919deb64fbf0aad1f6b3e78c1e937d83c63e93ed75e527		 rtf-objdata-decoded RTF \objdata at offset 0x81 1443 bytes

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