Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5069f36176df8b6e…

MALICIOUS

RTF / .DOC

26.4 KB First seen: 2021-09-15
MD5: 92ebf45b239e9c47b9ed9721732db3ed SHA-1: c501f359d18d901cfa1a2c32b4f80a4e3b935ccd SHA-256: 5069f36176df8b6e9582c8da04cc7f327e3f118a94c90db8406f8551864b7a33
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF file contains embedded OLE objects, specifically triggering heuristics related to Equation Editor vulnerabilities. The presence of objupdate and objautlink suggests that the embedded object is designed to be automatically activated upon opening the document, leading to the exploitation of the Equation Editor. This is a common delivery mechanism for exploiting known vulnerabilities to achieve arbitrary code execution.

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_off00001bcd.bin
18c35617f39079c45481ffeb055278f7931be20183e3feb7b73880795709f2f1
rtf-objdata-decoded RTF \objdata at offset 0x1BCD 1888 bytes