Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a3c6b924fdaf3d8d…

MALICIOUS

RTF / .DOC

19.2 KB
MD5: e4c21e04e20e6d6db67bdedc751cc75b SHA-1: ddf606af5e429fe95ebf6c1fe90104d4ca631541 SHA-256: a3c6b924fdaf3d8d40284376a9058a6c01e830615d5981cb64d2a425042499b3
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882), as indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics. The presence of OLE object data (RTF_OBJDATA) further supports this. The primary attack vector appears to be exploiting this vulnerability to achieve code execution, likely for the purpose of downloading and executing a subsequent stage.

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_off00000ad6.bin
a0b6ec85a0e88a4bb037759e5f7ed419c3ba09a32836fd97ea46de339a42d488
rtf-objdata-decoded RTF \objdata at offset 0xAD6 1544 bytes