Malicious PDF — malware analysis report

Static analysis result for SHA-256 a33730bcfafbc422…

MALICIOUS

PDF

87.8 KB Created: 2021-07-20 09:01:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 8c99857ae0f5a0645c60e88149da8f90 SHA-1: 5138fdd2df51c9cea8d7262ee5bbfe5ee347dc05 SHA-256: a33730bcfafbc42256c3bee20285320ddb9ed78356677764da26c3cc22e66acc
184 Risk Score

Malware Insights

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

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious. Heuristics indicate the presence of embedded JavaScript and a link farm pointing to compromised WordPress upload storage, suggesting an attempt to host malicious content. The 'SE_CALLBACK_LURE' heuristic strongly suggests the document's content is designed to trick the user into calling a fraudulent phone number, consistent with callback phishing or tech-support scams.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 8

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) or Microsoft license-boilerplate documents that carry no urgency or charge/dispute escalation.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://alfavs.eu/userfiles/file/kuralumurexikafoli.pdf In PDF document text
    • https://athensviptour.com/wp-content/plugins/super-forms/uploads/php/files/182ba059f598e2ca8c0925548aa4e50a/zuwezovutunobujitirubax.pdfIn PDF document text
    • http://www.lightingandhvacexpo.com/wp-content/plugins/super-forms/uploads/php/files/445649e4fe5177687b1b8200fa62c0fc/22650983543.pdfIn PDF document text
    • http://ongnuocdenhat.com/upload/files/91362982068.pdfIn PDF document text
    • http://gadkowski.pl/repository/filemanager/file/46580691997.pdfIn PDF document text
    • https://ceccargiurgiu.ro/userfiles/file/8852174096.pdfIn PDF document text
    • http://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a4cf66ca08---56581547676.pdfIn PDF document text
    • http://phunhai.net/upload/files/nitujeturox.pdfIn PDF document text
    • https://airflow-skateboards.com/upload/file/puxijodosowadanikeliboba.pdfIn PDF document text
    • http://bike-aholic.com/UserFiles/file/68469548441.pdfIn PDF document text
    • https://www.rowtheerne.com/wp-content/plugins/super-forms/uploads/php/files/7f354d2442335cc235351e9efe6c56e6/41726662307.pdfIn PDF document text
    • https://ncsccalgary.com/userfiles/files/fapebawusolaketip.pdfIn PDF document text
    • https://www.psalighting.com/wp-content/plugins/super-forms/uploads/php/files/7b17c17a564b25d6e912a3244b412941/15524144508.pdfIn PDF document text
    • https://refour.dk/wp-content/plugins/super-forms/uploads/php/files/d89a7f10821e60eb7c84cdaa60637619/votajeturamaduruxazonanaf.pdfIn PDF document text
    • http://nhuaduongnhapkhauaz.org/upload/files/45852483692.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608401b629653---kijifetuw.pdfIn PDF document text
    • http://driver-jazda.pl/upload/file/13170335414.pdfIn PDF document text
    • https://vietnamairlinescorp.org/js/ckfinder/userfiles/files/85616272755.pdfIn PDF document text
    • https://magatek.com/documents/file/jirupowazufuwum.pdfIn PDF document text
    • http://www.ponderosafestival.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0e22b17b38---basutajogiluf.pdfIn PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160858c791e5b5---kurufameden.pdfIn PDF document text
    • http://www.mostenpo.jp/userfiles/files/domuriposovujo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=squaw+valley+liftsPDF 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_off0000f46c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF46C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010c83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C83 10468 bytes
SHA-256: 98e435dfed182d2afbec50fdaa1001c3b3d3a3057d57182ae8cd4222e7c7b529
font_02_sfnt_off00012482.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12482 17564 bytes
SHA-256: 7de6324e8ad6bb3bc5ac0dbe1efce4a5bd738683a2046fc4a6af286a9a672d0d

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