Malicious RTF — malware analysis report

Static analysis result for SHA-256 a461f5cc81da5f2c…

MALICIOUS

RTF

82.0 KB First seen: 2024-08-23
MD5: 92f62e534dc12ae19d56d691befb3127 SHA-1: d70dd78b2218839911f2cce4af485185c02faae0 SHA-256: a461f5cc81da5f2c57bf6a2d3fcca1a77ddcd43b47dd5b38ab04822ba7e10840
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1129 Shared Modules

The file is an RTF document containing OLE object data and specifically triggers heuristics related to Equation Editor exploitation. The presence of `RTF_EQUATION_EDITOR`, `RTF_OBJAUTLINK`, `RTF_OBJUPDATE`, and `RTF_OBJDATA` strongly indicates that the document is designed to exploit a vulnerability in the Equation Editor component to achieve code execution. This is a common technique for delivering secondary payloads.

Heuristics 4

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off00001b73.bin
bdfb3ad2f6c671230c9c17793c48fe82671cfac69affbbbc11af154a89e5f7b6
rtf-objdata-decoded RTF \objdata at offset 0x1B73 1712 bytes