Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf981fb901194e69…

MALICIOUS

PDF

96.5 KB Created: 2021-09-06 01:01:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 4bebf27cff119c8caba2af2acdb0788c SHA-1: d496b90c8abd5db9f3a991c99b02202177136dc5 SHA-256: cf981fb901194e69eadeb6d3f04651e275dc7a47f10b4592c5e627ed70a600a9
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating it's a phishing or trojan delivery mechanism. It contains a large number of external URIs, many pointing to compromised WordPress sites, suggesting it functions as a link farm to lure victims to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9820

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://ketchas.ru/uplcv?utm_term=sight+singing+exercises+pdf PDF link annotation
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/1611495c1d7533---nuroguf.pdfIn PDF document text
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/0c68011b645e902ebc5866d44ab2015c/dulejiwabanupubugiwo.pdfIn PDF document text
    • http://mim2010.ru/userfiles/file/67522921010.pdfIn PDF document text
    • http://zonwering-nederland.com/ckfinder/userfiles/files/jarulaloxo.pdfIn PDF document text
    • http://historico.uts.edu.co/portal/app/ckfinder/userfiles/files/54409455000.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c8fd2961db1---35021662952.pdfIn PDF document text
    • https://msr-hudsonproperties.com/wp-content/plugins/super-forms/uploads/php/files/7ff63b6dba9d645840d7b9de4e7a818d/fofotagej.pdfIn PDF document text
    • http://lacasedescaraibes.fr/file/5598707750.pdfIn PDF document text
    • https://gpuhub.net/wp-content/plugins/super-forms/uploads/php/files/b0ugec9mh9kku8mojbq37a5i0a/13465413159.pdfIn PDF document text
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/ed2f1227b236c90c791d8059c574df48/jedakok.pdfIn PDF document text
    • http://thaihotelsale.com/FileData/ckfinder/files/20210822_57CBA3E25B84B039.pdfIn PDF document text
    • http://tekizolasyon.com/ckfinder/userfiles/files/41177857036.pdfIn PDF document text
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/4bfd6a616aae1ef489a22a92aba457e8/dupagulezegow.pdfIn PDF document text
    • https://autotrilogy.com/wp-content/plugins/super-forms/uploads/php/files/04d87eb5697788fb28a93d6428f45ece/dolabe.pdfIn PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d5b7bda74a8---23928323665.pdfIn PDF document text
    • http://bischofs-scheune.de/userfiles/file/83854455335.pdfIn PDF document text
    • http://maturitni-ples.eu/UserFiles/File/buwopojerivet.pdfIn PDF document text
    • http://zs-oilfieldequip.ru/d/files/buwajevofidutafofozulate.pdfIn PDF document text
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/n92202nmjimuvj2klm33dqpm4t/towuxesutulugemij.pdfIn PDF document text
    • https://cyc-catering.pe/disac/userfiles/file/16006051239.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d2c19d517c---jejotetebenotolazetutare.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/dibajidexofasakafesosa.pdfIn PDF document text
    • http://daiichilogistics.com/uploads/news_file/50414332975.pdfIn PDF document text
    • http://mwflower.com/upimagesfile///vemezisexosudavenuf.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/c25a9ad49ef7f244950744d092ff6150/fejemikurukubaz.pdfIn PDF document text
    • http://daydala.com/userfiles/file/74758985341.pdfIn PDF document text
    • 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_off00011767.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11767 10748 bytes
SHA-256: acf4157a558f5ad84ab9142f0bcbcd1842e7a065d05ff78274540d58464c38c6
font_01_sfnt_off00012fda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FDA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000147ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x147EC 18120 bytes
SHA-256: ce0550b67bec734eba46a3ba8d4a8990722c44ed2cf2e38788b002b4efdc7505

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