Malicious RTF — malware analysis report

Static analysis result for SHA-256 d127a6ef3f9acfce…

MALICIOUS

RTF

4.1 KB First seen: 2021-07-07
MD5: 402f0f03a1c22a4f5d9400117aa858c0 SHA-1: 2f3912540bd053e4f1de74eb199d1f778e8daf71 SHA-256: d127a6ef3f9acfcea39ac3cca973ecfe9e75f75b172f67b6da3007470987c00b
120 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and specifically triggers heuristics related to the Equation Editor vulnerability. The \objupdate directive forces the activation of this embedded object, leading to the exploitation of the Equation Editor to execute arbitrary code. This is a common technique for delivering malicious payloads via email attachments.

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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000b1.bin rtf-objdata-decoded RTF \objdata at offset 0xB1 1813 bytes
SHA-256: cd8c619ffe9ce0f1ed867ac43a88da5274b924c1284b1825014f4491ff05c6d3

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