Malicious RTF — malware analysis report

Static analysis result for SHA-256 8ea8fa1a31819761…

MALICIOUS

RTF

661.9 KB
MD5: 85ac7e1bb3a626ed3da28b9a37ecb19d SHA-1: 0ea433ba453e53162bb903cb3c69d075478903f3 SHA-256: 8ea8fa1a31819761e6997035f62e95ab894053fb630f9f2adeb2a44686166937
220 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of OLE object manipulation, specifically related to Composite Monikers and the ".objupdate" directive, which are hallmarks of CVE-2017-8570 exploitation. This vulnerability is known to be used for dropping and executing script files, such as SCT files, enabling further stages of an attack. The presence of multiple OLE objects and the critical heuristic firing for CVE-2017-8570 strongly suggest this exploit vector.

Heuristics 6

  • Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570
    RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • 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 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000007da.bin
7da7fe93a59d208477a5975b04662f459030b02761ccd15069f11c0e482e54fe		 rtf-objdata-decoded RTF \objdata at offset 0x7DA 221081 bytes
objdata_01_off00006f89.bin
e918886f3a8349162fa2406f3c1678afd5efa742ca65ea47a507aa5d667c2dde		 rtf-objdata-decoded RTF \objdata at offset 0x6F89 221054 bytes
objdata_02_off0007743a.bin
51ef705eef602ac6eb91c2063c8f50d4e54b5e051b60429031d41133bc7df645		 rtf-objdata-decoded RTF \objdata at offset 0x7743A 2632 bytes
objdata_03_off000789dd.bin
e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7		 rtf-objdata-decoded RTF \objdata at offset 0x789DD 12297 bytes

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