Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 21d9ecfc682503aa…

MALICIOUS

RTF / .DOC

15.7 KB
MD5: f4c97c2ec7d1f9c62469397486c6176d SHA-1: 0ec8a213c61159b3e34d87b5f31f07fb0beb4990 SHA-256: 21d9ecfc682503aaced06530ef4b4d618ae56966168330d868ef8bc97f72d97f
120 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE object data, specifically triggering the Equation Editor vulnerability. The \objupdate directive forces the activation of this embedded object, leading to code execution. This is a common technique for delivering secondary payloads, though no specific payload or download URL was directly extracted from this sample. The heuristics strongly indicate exploitation of the Equation Editor.

Heuristics 3

  • 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.
  • \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_off00000625.bin
7d3cd5138a5d089c42b694d50a23916e74d47586fdf4c90ef53a01d946a12de1
rtf-objdata-decoded RTF \objdata at offset 0x625 1843 bytes