Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 167ab63563aa6628…

MALICIOUS

RTF / .DOC

9.4 KB First seen: 2022-03-15
MD5: 05cb0105023aba7f791601c53cc4dbc9 SHA-1: efc92228f854a371b67517bf4e3e3ddd04ce52c8 SHA-256: 167ab63563aa66280fe2c4462e0f1c6214c4fd061ec60f1fda236a6d96c0909f
200 Risk Score

Malware Insights

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

The RTF document contains multiple heuristics indicating the exploitation of CVE-2017-11882 through an embedded Equation Editor object. The presence of \objupdate and \objdata sections, along with the specific ProgID 'eQUAtIOn.3', strongly suggests this vulnerability is being leveraged. This technique allows for arbitrary code execution, likely as part of a spearphishing attachment delivery chain.

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_off00001572.bin
238fef9bc6e9a955a515897f29b36cb893e0d13ab1d6591bab4079bc20f435e3		 rtf-objdata-decoded RTF \objdata at offset 0x1572 1953 bytes

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