Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fb3bd8c3de2877cd…

MALICIOUS

RTF / .DOC

3.8 KB
MD5: 9d9c21b719efa3bd055979c6a8f619e6 SHA-1: 042a9f73b6aa9c514eb0f144a7f1d4ddc91ec782 SHA-256: fb3bd8c3de2877cdef3a6e26d43cb2168fe6b317d1fc5ebde3dea47f26593ce0
120 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data and specifically triggers the Equation Editor vulnerability. The ".objupdate" directive forces the activation of this embedded object, leading to the exploitation of the Equation Editor to achieve arbitrary code execution. This is a common delivery mechanism for initial access.

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_off000000b7.bin
192b2dc61b6822c4e090b000f7a3dd7565e6c64087b0fafb9228fdf42fa3be65
rtf-objdata-decoded RTF \objdata at offset 0xB7 1697 bytes