Malicious RTF — malware analysis report

Static analysis result for SHA-256 a83828f8626eb716…

MALICIOUS

RTF

4.2 KB First seen: 2022-08-23
MD5: 7777a4440ebe0f9e865ce11f68200eea SHA-1: e8a57986002201041c5033359e54545e9f8cd4af SHA-256: a83828f8626eb7160b45410483f663f29ca2ab7c0f72151f9e2cdb8d555a9797
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains OLE object data and specifically triggers heuristics related to Equation Editor exploitation, indicating the use of CVE-2017-11882. This vulnerability allows for the execution of arbitrary code when the embedded OLE object is activated.

Heuristics 5

  • 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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000b8.bin
1ae1472fd0503f227ebba57ad0da667fc05a739b5ee08df46f0b530c3766f373		 rtf-objdata-decoded RTF \objdata at offset 0xB8 1984 bytes

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