Malicious RTF — malware analysis report

Static analysis result for SHA-256 eac6f941d990e293…

MALICIOUS

RTF

3.9 KB First seen: 2021-07-02
MD5: 787accd5a6a5a7483ed7ff5cc9de176d SHA-1: 0a343c211335da07a4866e858bcbb3eb9d28a098 SHA-256: eac6f941d990e2930f3bcde4abbbe54bd1c57683addf5ce19c8cd915af339344
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE objects and specifically triggers heuristics related to CVE-2017-11882, indicating exploitation of the Equation Editor vulnerability. This vulnerability allows for arbitrary code execution when the document is opened, likely as a spearphishing attachment.

Heuristics 5

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
  • 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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000008a.bin rtf-objdata-decoded RTF \objdata at offset 0x8A 1737 bytes
SHA-256: e952b6504b7b29549996250a0c3bc2aeb542672a2eba5acdb4fc38ac3a670099

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