Malicious RTF — malware analysis report

Static analysis result for SHA-256 19189488de1fd39f…

MALICIOUS

RTF

2.95 MB Created: 2025-02-13 01:23:00 First seen: 2025-02-18
MD5: cdfbf782d0ca7454dc055a11024f89e2 SHA-1: e8d9ca661a27996ebc85e4295833f06b43819015 SHA-256: 19189488de1fd39f36be1f4bda1b58bcf33bc8c911814691c2ce5882ef40b959
322 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains multiple indicators of malicious activity, including embedded OLE objects and specific heuristics pointing to the CVE-2017-11882 vulnerability. The presence of large hex-encoded data within an OLE object, along with a PE header, strongly suggests the embedding of a second-stage executable. The `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` firings confirm the exploitation vector.

Heuristics 9

  • 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.
  • 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 ~1048KB 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://ocsp.digicert.com0C
    • http://ocsp.digicert.com0A
    • http://ocsp.digicert.com0X
    • 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://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/
    • 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
    • http://cacerts.digicert.com/DigiCertAssuredIDRootCA.crt0E
    • http://crl3.digicert.com/DigiCertAssuredIDRootCA.crl0
    • https://www.verisign.com/cps0*
    • http://logo.verisign.com/vslogo.gif04
    • http://crl.verisign.com/pca3-g5.crl04
    • http://cacerts.digicert.com/DigiCertTrustedRootG4.crt0C
    • http://crl3.digicert.com/DigiCertTrustedRootG4.crl0
    • http://crl3.digicert.com/DigiCertTrustedG4RSA4096SHA256TimeStampingCA.crl0��
    • http://cacerts.digicert.com/DigiCertTrustedG4RSA4096SHA256TimeStampingCA.crt0

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00022ce6.bin
d32a4e569994d1a24209d737d2995c4ca3b571402687fe4aeb47f3681ff162ee		 rtf-objdata-decoded RTF \objdata at offset 0x22CE6 495698 bytes
objdata_01_off001205bc.bin
56684de9a3a82fd5fe392f331efb0aef7d8f1ca301483bc8e8af8263a6e0e72b		 rtf-objdata-decoded RTF \objdata at offset 0x1205BC 534490 bytes
rtf_svb_00002c19.zip
d39b64319316e088a3b732b0bbaad03692be6c735566f33d475288af16e459ea		 rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x2C19 8890 bytes

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