Malicious RTF — malware analysis report

Static analysis result for SHA-256 e505c9c09e605a6e…

MALICIOUS

RTF

87.0 KB First seen: 2019-08-04
MD5: a24e4d61160080736b53acc6560b9ac0 SHA-1: ef3ed73915b9f487e748bd9f462f79d70610d251 SHA-256: e505c9c09e605a6eec8daf0bcb91f8ac2181860423e5a3e46393cad75b9873c2
200 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains evidence of the CVE-2017-11882 vulnerability related to Microsoft Equation Editor. This vulnerability allows for arbitrary code execution when the embedded OLE object is activated, likely leading to the download and execution of a secondary payload.

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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00008aba.bin rtf-objdata-decoded RTF \objdata at offset 0x8ABA 1399 bytes
SHA-256: e0f7a693101f3d961baee631cc7dc484fc71eeaffb8a80056355a7e266461e29

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