Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 582b81f8acda1193…

MALICIOUS

RTF / .DOC

4.2 KB
MD5: 873605f2ddac19a9d261d28e7a314923 SHA-1: 97b2307216bf8e08063f0cc6c2e881d313cea89b SHA-256: 582b81f8acda1193621279e0b1eafc8b2f28dfd2a90f3b60b11dfbe0553c0d7b
180 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that leverages the Equation Editor (EquatiOn.3) to exploit CVE-2017-11882. This exploit allows for arbitrary code execution upon activation. The presence of RTF_OBJDATA, RTF_OBJEMB, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly indicates this attack vector.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • \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
  • 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_off00000043.bin
1458063dde76761e05b67c8e9aa5143c0e6005bc49ef75cbf74a5c12a96824ec		 rtf-objdata-decoded RTF \objdata at offset 0x43 2023 bytes

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