Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4bcb6568d06c3593…

MALICIOUS

RTF / .DOC

6.1 KB First seen: 2022-11-30
MD5: e530aa1caacfa1a806c9e0cdd0003581 SHA-1: cbe9a5c4f1a7c658d190dafd121855151bec77d4 SHA-256: 4bcb6568d06c35933731f64178b152976714aaa022eaf6131874e9665554d56a
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) for code execution. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics strongly indicates this exploit. The `RTF_OBJAUTLINK` and `RTF_OBJUPDATE` heuristics suggest that the embedded OLE object is automatically activated upon opening the document, leading to the exploitation.

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_off00000988.bin
95091a17af43b7e05e3b1059f65875d75f2f76124fcdd5e3ecb910269dbe1572		 rtf-objdata-decoded RTF \objdata at offset 0x988 1844 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.