Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 77b8a3571b3f1e51…

MALICIOUS

RTF / .DOC

4.2 KB First seen: 2022-03-15
MD5: 243e173b1bf672894f6eb38cc075514f SHA-1: 4d4a39e9cf892e6247fe358ea53e04ed9394fa82 SHA-256: 77b8a3571b3f1e5165fc691b7cb89079993816609e080859d663344584cef12e
120 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects and specifically triggers the Equation Editor vulnerability. The ".objupdate" directive forces the activation of these embedded objects, leading to the execution of arbitrary code. This is a common technique for delivering exploits via email attachments.

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_off00000087.bin
0b1295a29905aae49aff90f2e9c33b3525a0b880537f9007d73514714742b7d3
rtf-objdata-decoded RTF \objdata at offset 0x87 1855 bytes