Malicious RTF — malware analysis report

Static analysis result for SHA-256 28c9f44aeabdfffe…

MALICIOUS

RTF

5.7 KB First seen: 2019-01-12
MD5: 944ed36eeea1c54f4419b73676bb1e53 SHA-1: cc586976e9a29065f6ac749ad62ace849bfa06dd SHA-256: 28c9f44aeabdfffe48c6a5a0162eb6e694799e81a3390d9f9f76ff4e1cae3e60
120 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, indicating exploitation of a known vulnerability (CVE-2017-11882). The \objupdate directive forces the activation of this object, leading to arbitrary code execution. This is a common technique for delivering secondary payloads, though no specific payload or C2 infrastructure was directly observed in this sample.

Heuristics 3

  • 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.
  • \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_off00000a54.bin rtf-objdata-decoded RTF \objdata at offset 0xA54 1608 bytes
SHA-256: 4634590ee273e25c908bef6ed258fc8e1828bfad3583db691bc11ee092d170a7

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