Win.Malware.Delf-6691246-0 — RTF malware analysis

Static analysis result for SHA-256 819da7b486542a02…

MALICIOUS

RTF

1.76 MB First seen: 2019-04-18
MD5: f6ddd975330c7e3ef0b814954e3e3b47 SHA-1: 97e834e59c630445dca2ba1a242a04b3b2458a04 SHA-256: 819da7b486542a024b9b072126db9460b5f5122f9785db8ef91e17227985febf
482 Risk Score

Malware Insights

Win.Malware.Delf-6691246-0 · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of exploitation, including the use of Composite Moniker and Equation Editor CLSID, strongly suggesting CVE-2017-8570. This vulnerability is known to drop SCT scripts, which are then executed. The presence of a PE header within the hex data and ClamAV detections for Win.Malware.Delf-6691246-0 further confirm the malicious nature and likely payload.

Heuristics 11

  • 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.
  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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.
  • ClamAV: Win.Malware.Delf-6691246-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Delf-6691246-0
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1821KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 7 \objdata section(s) — embedded OLE objects
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.
  • Suspicious extracted artifact medium 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.
  • 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.openxmlformats.org/drawingml/2006/main In RTF body

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000002c.bin rtf-objdata-decoded RTF \objdata at offset 0x2C 884 bytes
SHA-256: 08cb831cfd094f7193857584f98ebb419e336c73f0191f78a94fb322b6fcad85
objdata_01_off0004c6e8.bin rtf-objdata-decoded RTF \objdata at offset 0x4C6E8 102604 bytes
SHA-256: 35157ee17216cb72ffd90cc36322f4d9db156130bd852b967c9325212c3c51d5
objdata_02_off0007e8b3.bin rtf-objdata-decoded RTF \objdata at offset 0x7E8B3 651980 bytes
SHA-256: fc95e02165c7a967d1a6519579cc2ff67b3a29fc532d8b06c90ec4cb16eef61f
Detection
ClamAV: Win.Malware.Delf-6691246-0
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_MSF_REVERSE, SC_STR_VIRTUALALLOC, SC_STR_LOADLIBRARY Static shellcode analysis recovered API/import strings: LoadLibraryExA, VirtualAlloc, GetProcAddress, ExitProcess
objdata_03_off001bce89.bin rtf-objdata-decoded RTF \objdata at offset 0x1BCE89 382 bytes
SHA-256: 7c829894502990522aaee3764e10dad03b3c7476dec48c4e1d128bb9b9774910
objdata_04_off001bd1b9.bin rtf-objdata-decoded RTF \objdata at offset 0x1BD1B9 789 bytes
SHA-256: 87caf099a20fd4563d975979583365d98bc376a5fd992193cf5da7686fc18198
objdata_05_off001bd84a.bin rtf-objdata-decoded RTF \objdata at offset 0x1BD84A 2633 bytes
SHA-256: 1feb5f150bb35566d1a01fc59a357dc0ea34bc7498e0ec99bd939f6f848044b0
objdata_06_off001bed54.bin rtf-objdata-decoded RTF \objdata at offset 0x1BED54 4679 bytes
SHA-256: 0e2ce9d01b0df41beca1d9d003ff4bfe3998a96192a53992dd35145a081e0a27

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