Malicious PDF — malware analysis report

Static analysis result for SHA-256 a57dd459b3da0a0e…

MALICIOUS

PDF

85.0 KB Created: 2021-06-28 07:05:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 18055e8f2b5038807c76c34f04adb096 SHA-1: 2ba3f5387f52d50f83a694835599c7803101ad0d SHA-256: a57dd459b3da0a0ea8e8fe05d902d39c592ee1cf9b0e1e736038eeaaca9e0ae4
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains a large number of embedded links, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics indicates a deliberate attempt to obscure the final destination and leverage SEO tactics for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9834

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
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://oniceh.ru/uplcv?utm_term=system+of+equations+with+no+solution+example PDF link annotation
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/43a3e81a49c7bf22a0e6e3ed97c784d0/xukuxewademetipuriniwo.pdfIn PDF document text
    • https://specialbrands.gr/wp-content/plugins/super-forms/uploads/php/files/6153a54f30b0294c8845ce72c48cd576/62071020260.pdfIn PDF document text
    • https://xn--80aaaglcftt5alesfkk7f.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/ed6944da43b13a5fb3cc5af467b1f61f/44399300406.pdfIn PDF document text
    • http://brezov-gaj.si/uporabnik/file/nezibudufozazobu.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/160875c595ea75---95095691964.pdfIn PDF document text
    • http://ashioke.com/images/library/File/rodagosetoj.pdfIn PDF document text
    • https://www.rath-catering.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c35bd810d2f---39624861708.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bfe826ce25f---24267592842.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/9596tmlamiug76lq3ov1934eo7/16777082555.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2275a73fd0---85323544978.pdfIn PDF document text
    • https://visaonline-vn.com/wp-content/plugins/super-forms/uploads/php/files/f7v47q6i0qqc4tsumjeudasfmt/vifavogedubu.pdfIn PDF document text
    • https://anitacalderon.com/ckfinder/userfiles/files/sugisilo.pdfIn PDF document text
    • http://texmet.pl/userimages/file/65673793280.pdfIn PDF document text
    • http://nuraski.pl/wsg/userfiles/38658503124.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/6a8032f8d8ff832a2420fddc50fa7c67/75988616837.pdfIn PDF document text
    • https://www.kngroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5676c29e0c---jafera.pdfIn PDF document text
    • http://dom-nenilovo.ru/wp-content/plugins/super-forms/uploads/php/files/c732d21e7c83ebd20b6399dda1111828/27944463238.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084372bbf626---53904446817.pdfIn PDF document text
    • http://asesoriagarpe.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e1302b3a45---41922822233.pdfIn PDF document text
    • http://cafesezony.ru/fck_editor_files/files/87250351207.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/2dfsh8cvlc7uk13g16ng2ar76f/sakubabaxuzupipolumis.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/160890fab12ce9---boramurogegogabidosuxi.pdfIn PDF document text
    • http://www.training4thefuture.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c08e9a6e2d5---saloragexadaluxi.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16092ada4dea12---vojuserepud.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/56f0d103deac6d77added8e4eb755976/69292203796.pdfIn PDF document text
    • https://jjmassociates.com/wp-content/plugins/super-forms/uploads/php/files/8e75197be19043eaf8c8e1cd9f74442d/modoferomodajazibi.pdfIn PDF document text
    • http://softwarefactory.nl/images/file/86397934579.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_off0000e625.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE625 16984 bytes
SHA-256: b98e76a273913be811afbf5592a4f498f4b7aa2e6c2ac8ba1fcfb374e331bfac
font_01_sfnt_off00011255.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11255 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012a6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A6C 11148 bytes
SHA-256: 283b65fe6fb22bd124b532df0470f237f89ae5501dcd70a0856f7bce628be393

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