Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ef4241bfe9fb457b…

MALICIOUS

RTF / .DOC

26.8 KB
MD5: c881bbaab78ac29590881ae51a0caa9d SHA-1: 11fe2cb93dabe58bc89a3ba7ff6f58bb8f0829b3 SHA-256: ef4241bfe9fb457ba6d2d8b4afbba37aa46ac1a4287dc817a5ccf295dcdc1a6e
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that contains embedded OLE objects, specifically targeting the Equation Editor. The presence of RTF_EQUATION_EDITOR, RTF_OBJAUTLINK, and RTF_OBJUPDATE heuristics indicates that the document is designed to exploit a known vulnerability in the Equation Editor component to achieve code execution. This is a common technique for delivering malware. No scripts were extracted, and the document body was heavily obfuscated, preventing further analysis of the specific payload.

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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00002019.bin
ead7a76481149e3940ef5069e0a6a7b268f2ead93cc084072558613dc9871ce0
rtf-objdata-decoded RTF \objdata at offset 0x2019 1776 bytes