Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0fff85c16469321b…

MALICIOUS

RTF / .DOC

3.8 KB
MD5: b539fb5731b1ceaa1095dd33978a7d84 SHA-1: 7b5cbeb95ea466ce123b4b8cc5935b964cb8bd54 SHA-256: 0fff85c16469321bc30312f628e5f3d955bb086c20812c2b3f536e6dab2ea5c0
180 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 object data, specifically triggering heuristics related to the Equation Editor vulnerability CVE-2017-11882. The presence of objupdate forces OLE activation, indicating an attempt to execute embedded code. This pattern is commonly used to deliver malicious payloads via email attachments.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000ac.bin
fd973e276961ac3094efbd1ae8a15ce1353af74c75f9b62ac9e5c4797088fabf
rtf-objdata-decoded RTF \objdata at offset 0xAC 1719 bytes