Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1e2fdb811fe57821…

MALICIOUS

RTF / .DOC

12.1 KB First seen: 2022-02-23
MD5: b05bf67b8b2bf8f784d43aa9b51f5336 SHA-1: 720e2c6b17b784db0a1424f998c5b9e698628dcf SHA-256: 1e2fdb811fe57821ee77f20c66996c8a52c64cd819326bf92f94976ed190d811
121 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE objects, specifically targeting the Equation Editor vulnerability. The \objupdate directive indicates that the embedded object will be activated automatically upon opening the document. This technique is commonly used to achieve arbitrary code execution, typically to download and execute a second-stage payload. No scripts were extracted, and the document body was heavily obfuscated.

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_off00001f97.bin
866f89e55e636d053f0bde4266748c36f82e7b5d14072903e75834c2391272f5
rtf-objdata-decoded RTF \objdata at offset 0x1F97 1935 bytes