Malicious RTF — malware analysis report

Static analysis result for SHA-256 051a19599ed53c23…

MALICIOUS

RTF

5.03 MB Created: 2025-09-16 18:10:00 First seen: 2025-12-05
MD5: 82b1f625bb94646b508d433eb5600cf7 SHA-1: 2fbf236441e3bbfdfab3883d4ee9a1f2638eb02b SHA-256: 051a19599ed53c233debbd32daa4645bae40e766b387d77a44428f61ec1046a6
422 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1204.002 Malicious File: User Execution

The RTF file contains multiple critical heuristic firings indicating exploitation of Equation Editor (CVE-2017-11882) and MSXML (CVE-2017-8759). It also contains a hidden package related to a Word/OLE security bypass (CVE-2026-21514). These vulnerabilities are typically used to download and execute a second-stage payload, likely a PE file, as indicated by the presence of hex-encoded MZ headers.

Heuristics 11

  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • 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.
  • 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.
  • CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514
    RTF contains a hidden \svb hex package with DrsE2oDoc and downRevStg drawing compatibility parts. This matches an observed CVE-2026-21514 exploitation shape that manipulates Word's internal document structure and trust decisions.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • 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 ~2266KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \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://ocsp.thawte.com0
    • http://schemas.microsoft.com/office/word/2003/wordml
    • http://cs-g2-crl.thawte.com/ThawteCSG2.crl0
    • http://crl.thawte.com/ThawtePCA.crl0
    • https://www.globalsign.com/repository/0
    • http://ocsp.globalsign.com/ca/gstsacasha384g40C
    • http://secure.globalsign.com/cacert/gstsacasha384g4.crt0
    • http://crl.globalsign.com/ca/gstsacasha384g4.crl0
    • http://ocsp2.globalsign.com/rootr606
    • http://crl.globalsign.com/root-r6.crl0G

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000af73f.bin
0b88c90a14da1a31e9a0bca85cc3abb86a1a1c54da5568c56e1aea1fc7d9d932		 rtf-objdata-decoded RTF \objdata at offset 0xAF73F 1029274 bytes
objdata_01_off002b17cf.bin
24ee741dd41bc27803d80f81b66eba686fe8f5d17bd847727dc5d94834bd3188		 rtf-objdata-decoded RTF \objdata at offset 0x2B17CF 584826 bytes
rtf_svb_00000009.zip
2352c9fffd0fd8eba341b4fd80ae0a94a85929bec042e2061b1f17cd52df50f2		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x9 116884 bytes

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