Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 64488d0945d0b029…

MALICIOUS

RTF / .DOC

2.51 MB Created: 2019-09-17 13:59:00
MD5: f8d74c4e175a21cb8010a56b455d56e0 SHA-1: c2fc75b55d8aadb0486adbf6c172dee41591d346 SHA-256: 64488d0945d0b02943797f1886fd7d5f075f61445b6c41071a0c77b40eb3649f
182 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and specifically triggers heuristics related to the Equation Editor, indicating exploitation of CVE-2017-11882. This vulnerability allows for arbitrary code execution, which is the primary mechanism for this attack. The presence of ".objupdate" further confirms the intent to force OLE object activation and exploit.

Heuristics 6

  • 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
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2{
    • http://bit.ly/38j9Oyg

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00260152.bin
47fbe8d18707736009c009ecd18a08fa035a7f32f9dd904e6c243c3889ac89c0		 rtf-objdata-decoded RTF \objdata at offset 0x260152 1415 bytes

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