Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f55ca9ebf1e7d21a…

MALICIOUS

RTF / .DOC

14.4 KB First seen: 2022-11-17
MD5: de174ee97d0af4b5750c4deb814ebb1e SHA-1: c6d0837a2720d293d9a059f8d27ced2bead0c39c SHA-256: f55ca9ebf1e7d21a88ca4cb50d579a16e943d0186bf95e5dbf7192835752c1c3
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF file contains OLE object data and specifically triggers heuristics related to Equation Editor exploitation (CVE-2017-11882). The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` strongly indicates an attempt to exploit this known vulnerability. The `RTF_OBJUPDATE` heuristic suggests the OLE object is automatically activated, leading to arbitrary code execution.

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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001984.bin
92f0a6dbc12b645e2fced1c5dae8aa5acd51afa29efa59d4fb0bb2cdd9b7e94a		 rtf-objdata-decoded RTF \objdata at offset 0x1984 1814 bytes

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