Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c78a1ef10324fee5…

MALICIOUS

RTF / .DOC

19.3 KB
MD5: 118224e6dd2a2b5c3fdb5af7115b315a SHA-1: e0076331af4c32a460fae0413dff2b371025649a SHA-256: c78a1ef10324fee5e8f829ac91fbf159e5d5f59db0b99ba424e17a0ca79fbd15
160 Risk Score

Malware Insights

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

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) to execute arbitrary code. The presence of OLE object data and specific RTF heuristics like RTF_EQUATION_EDITOR, RTF_OBJAUTLINK, and RTF_OBJUPDATE strongly indicate this exploit. The embedded OLE object likely contains the malicious payload, which is automatically activated upon opening the document.

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_off00001ebd.bin
7ea6259f11760b02c1012388b7a1464fd653d367d7ff797f9d68d1dd70828abc
rtf-objdata-decoded RTF \objdata at offset 0x1EBD 1533 bytes