Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cd4f78c4f7135c1…

MALICIOUS

PDF

83.1 KB Created: 2021-09-08 17:56:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: a3287ddccdd84dacaa010c0f115d47f8 SHA-1: 156f95afe30ad0b1cc89a49548e3275445180820 SHA-256: 4cd4f78c4f7135c13ccf134d61f215bda13442b23d9812a308aadd44d0779076
176 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating a malformed exploit stream and a link farm pointing to compromised CMS uploads and disposable hosting. The PDF contains numerous embedded URLs, many of which are hosted on compromised or suspicious domains, suggesting a phishing or malware distribution attempt. No scripts were extracted, but the PDF structure and URL analysis strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9962

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://tlw.ro/UserFiles/file/mekenugaxamejiwa.pdf In PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/161323502c81aa---razebetifazumuvizemu.pdfIn PDF document text
    • https://journalofcritique.com/ckdosyalari/upload/files/86425152028.pdfIn PDF document text
    • http://bulk-supplies.com/userfiles/file/64929849325.pdfIn PDF document text
    • http://gpkoaee.ru/ckfinder/userfiles/files/31532222820.pdfIn PDF document text
    • http://www.addvanceo.info/userfiles/files/94773371517.pdfIn PDF document text
    • http://odontoflash.eu/userfiles/files/97348705550.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613440ee363a1---10496461423.pdfIn PDF document text
    • http://lnaixi.com/userfiles/file/20210908202553_219301046.pdfIn PDF document text
    • http://owop.challengersports.com/ckfinder/userfiles/files/jurebadidefagutewugabimo.pdfIn PDF document text
    • http://a-kamen.com/userfiles/file/wovipofavopanupopudise.pdfIn PDF document text
    • http://one9five.com/userfiles/files/69494353158.pdfIn PDF document text
    • http://radio-salsa.com/php/rs/filesupload/file/torakej.pdfIn PDF document text
    • http://depcip.com/app/views/panel/ckfinder/userfiles/files/7606431859.pdfIn PDF document text
    • https://bokaichenyu.com/upload/files/57049892278.pdfIn PDF document text
    • http://ildongwire.com/userfiles/file/vonizunafugufusepeku.pdfIn PDF document text
    • https://www.intermediastudios.com.mx/wp-content/plugins/super-forms/uploads/php/files/65fa5b4eacac610a6c730e5166aab34d/guvaguvi.pdfIn PDF document text
    • http://hydrogears.com/survey/userfiles/files/nikexoja.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/161310b8b99ffa---18935719010.pdfIn PDF document text
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16130edaea3ef4---93877705011.pdfIn PDF document text
    • http://bowlingkillers.com/imgdb/files/timeguvepugeto.pdfIn PDF document text
    • http://adhunikjewellers.com/ckfinder/userfiles/files/kelufuzujigedaminarano.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=shakeology+strawberry+recipes+pdfPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000df10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF10 17660 bytes
SHA-256: 34012666f49324b6edef5bc4f96720937eb045ded9231187ded3ef748b052e05
font_01_sfnt_off00010cec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CEC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012503.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12503 11300 bytes
SHA-256: a9df36dc4c63852cf8850c830c3151285edcb40bea78dde91d4a36012a4b4639

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