Malicious RTF — malware analysis report

Static analysis result for SHA-256 a5b0789060bd3393…

MALICIOUS

RTF

296.0 KB First seen: 2021-04-25
MD5: 1ff387133f2e3a29470a43f3a52d36b9 SHA-1: 5c3d3ab0d6cebd7908035c86c79f24fa8add301f SHA-256: a5b0789060bd3393b4ec64eecf081baf662eab3f75922ab1e7dd101981b3c8ab
340 Risk Score

Heuristics 9

  • 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.
  • CVE-2017-0199 / CVE-2017-8759 (OLE2Link auto-activated remote loader) critical CVE related RTF_OLE2LINK_REMOTE_MONIKER_LOADER
    RTF embeds an OLE2Link object that is force-activated with \objupdate (no user interaction on open) and fetches a remote second stage — through an INCLUDETEXT/INCLUDEPICTURE field or the OLE object's own moniker. This is the OLE2Link auto-update attack path shared by CVE-2017-0199 (server returns an HTA/scriptlet) and CVE-2017-8759 (server returns a SOAP WSDL the .NET parser compiles). Office processes the fetched response through the same code path; the specific CVE depends on the now-unreachable server content type.
  • 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.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000bb5.bin rtf-objdata-decoded RTF \objdata at offset 0xBB5 40450 bytes
SHA-256: 72a316ad122b032052d4fdd7e5a9715bf70a54a8dbdd908a15102b43210c301e
objdata_01_off00007364.bin rtf-objdata-decoded RTF \objdata at offset 0x7364 40423 bytes
SHA-256: 014915336eede55f94050221f6ed7d2abbb382a61d707f1417fc6f26bc9ba6da
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off0001bc75.bin rtf-objdata-decoded RTF \objdata at offset 0x1BC75 2632 bytes
SHA-256: 3cd3b7d42e5855c90d6d11c54ef2670ed8970441480cc23f7d39ef08fa1c935b
objdata_03_off0001d218.bin rtf-objdata-decoded RTF \objdata at offset 0x1D218 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7