Malicious RTF — malware analysis report

Static analysis result for SHA-256 cb61530e07a137eb…

MALICIOUS

RTF

60.0 KB First seen: 2019-01-25
MD5: 36bab8c6a0b48f41e671f36b425f0099 SHA-1: 52e3d02c1d80b0f05c511e896c5d7377ba2a2bb1 SHA-256: cb61530e07a137ebe8e3deea39125dcfd54f65a299b0ca6dc4795cd4f6dfcdde
120 Risk Score

Malware Insights

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

The RTF file contains critical heuristics indicating the use of the Equation Editor vulnerability (RTF_EQUATION_EDITOR) and OLE object activation (RTF_OBJDATA, RTF_OBJUPDATE). This strongly suggests exploitation for client execution. The file is likely delivered as a spearphishing attachment, aiming to download and execute a secondary payload.

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_off000004f9.bin rtf-objdata-decoded RTF \objdata at offset 0x4F9 3455 bytes
SHA-256: 1391a4910f4779df0c53baeb314dd90ddf7ec137b83e10a7dbc69b4dbd4f9f3a

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