Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6fabce85c63df5b4…

MALICIOUS

RTF / .DOC

3.7 KB First seen: 2021-09-29
MD5: 6fc7dffb72c2240811a4fa491db68f9f SHA-1: b6f3786449ac8c23f86912fac94298bcb068eda7 SHA-256: 6fabce85c63df5b451d7122ae6e660776279203677a2b371a6374fb1033c84c5
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an RTF document containing embedded OLE objects, specifically triggering heuristics related to the Equation Editor vulnerability. This indicates an attempt to exploit a client-side vulnerability for code execution. The presence of ".objdata" and ".objupdate" further supports the exploitation of OLE object handling within RTF documents. The document body contains only a numeric string, providing no further context on the lure.

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_off000000a1.bin
1abe56fcbabd9ee80e9041dfc367c813f71c062430bcd1f4769eb159a26d5d80
rtf-objdata-decoded RTF \objdata at offset 0xA1 1596 bytes