Malicious RTF — malware analysis report

Static analysis result for SHA-256 b9a877b5ed9d75cc…

MALICIOUS

RTF

336.8 KB First seen: 2020-02-04
MD5: b4944e75def86a11f76e8e2eaf0d5f07 SHA-1: 65d18edc5461e038ff0a61ec8f115580944e187e SHA-256: b9a877b5ed9d75cc9b44d638b322eb1b359cb0037eb4a465df81cff45b329449
120 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object and triggers heuristics related to the Equation Editor vulnerability. This indicates the file is designed to exploit a known vulnerability in the Equation Editor component to achieve code execution upon opening. The presence of ".objupdate" further suggests an attempt to force OLE object activation.

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_off00000297.bin rtf-objdata-decoded RTF \objdata at offset 0x297 106347 bytes
SHA-256: efc156533ac71e4c982502a9c44a6d0e581339c29bc9cc6ad44fb0432630fa68

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