Malicious RTF — malware analysis report

Static analysis result for SHA-256 221f0dfce9d3d8c7…

MALICIOUS

RTF

5.01 MB Created: 2025-09-16 18:10:00 First seen: 2025-11-20
MD5: 82bf1f5d8a84a9c7358aeb01f98d54bd SHA-1: ff0d9871967c6e1376ef4634993c30d8545d7de1 SHA-256: 221f0dfce9d3d8c7aa9489cf39a02fedbeed7837120338cdf77f3c5168bc021d
422 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects and exploits known vulnerabilities in Microsoft Equation Editor (CVE-2017-11882) and MSXML (CVE-2017-8759). The presence of large hex-encoded data blocks and a PE header within the OLE object suggests the embedding of a malicious executable. The document body, containing calendar data, is likely a lure to disguise the malicious intent.

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 ~2038KB 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.verisign.com0
    • http://schemas.microsoft.com/office/word/2003/wordml
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/t/pg/
    • http://ns.adobe.com/xap/1.0/sType/Dimensions#
    • http://ns.adobe.com/xap/1.0/g/
    • http://ns.adobe.com/illustrator/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://ns.adobe.com/pdf/1.3/
    • http://www.adobe.com/content/dam/Adobe/en/products/acrobat/pdfs/adobe-acrobat-xi-export-pdf-comments-to-word-tutorial-ue.pdf
    • http://www.adobe.com/products/acrobat
    • http://www.adobe.com/products/acrobat/shared-PDF-document-reviews.html
    • http://www.adobe.com/products/acrobat/esign-with-echosign.html
    • http://www.adobe.com/products/acrobat/file-compare-two-pdf-files.html
    • http://www.adobe.com/products/acrobat/pdf-version-control-sharepoint-integration.html
    • http://www.adobe.com/products/acrobat/pdf-file-password-permissions.html
    • https://www.verisign.com/rpa
    • http://csc3-2010-crl.verisign.com/CSC3-2010.crl0D
    • https://www.verisign.com/rpa0
    • http://csc3-2010-aia.verisign.com/CSC3-2010.cer0
    • https://www.verisign.com/cps0*
    • http://logo.verisign.com/vslogo.gif04
    • http://crl.verisign.com/pca3-g5.crl04
    • 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
5e8c0de5788e3c8bbac42277a6faaed4e5c75ce8291348359496fc29defca062		 rtf-objdata-decoded RTF \objdata at offset 0xAF73F 915426 bytes
objdata_01_off00279e5f.bin
24ee741dd41bc27803d80f81b66eba686fe8f5d17bd847727dc5d94834bd3188		 rtf-objdata-decoded RTF \objdata at offset 0x279E5F 584826 bytes
rtf_svb_00000009.zip
2352c9fffd0fd8eba341b4fd80ae0a94a85929bec042e2061b1f17cd52df50f2		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x9 116884 bytes

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