Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 409992d0436f5256…

MALICIOUS

RTF / .DOC

123.0 KB First seen: 2023-08-16
MD5: 13a3f6521c13ba0c632db67c7041c977 SHA-1: 5dd8153d6daa7d000fbb5c9c9760bc2f57b27a1c SHA-256: 409992d0436f5256bc7bf86bbe08d7c41d13103c59f1cfc35885d1608a3e7286
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits a vulnerability in the Equation Editor. The document body contains a lure instructing the user to 'click Enable editing from the yellow bar above' to bypass security settings. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly indicates exploitation of this component.

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.
  • \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 1 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003e2b.bin
ceef8bebc1cccb958cf1ad3dc21a954fb9facf75e1df5fb53e110422ea84f0ca
rtf-objdata-decoded RTF \objdata at offset 0x3E2B 1908 bytes