Malicious PDF — malware analysis report

Static analysis result for SHA-256 ff99a10452c371ae…

MALICIOUS

PDF

78.0 KB Created: 2021-06-25 22:27:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2026-06-05
MD5: e20051694d697f7b1138080e663cd8d3 SHA-1: 692a1cc42bf4aad0adc749dfb486fe2d437c1759 SHA-256: ff99a10452c371ae37a89690277f10f4d8b858a34d0530ff77dc598314dbf1ec
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of external URIs, many of which point to compromised WordPress installations or disposable domains. This suggests the document is primarily functioning as a link farm, likely for SEO manipulation or to distribute malicious content. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 5

  • 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://nomylo.ru/uplcv?utm_term=throws+crossword+clue+5+letters PDF link annotation
    • http://mosjob.ru/images/file/vidupobilobiwoxewewone.pdfIn PDF document text
    • http://geologicatoscana.eu/userfiles/files/71873545188.pdfIn PDF document text
    • https://ecobox.eng.br/wp-content/plugins/super-forms/uploads/php/files/gv0ni8qbrn2r07sujo56nkn7cg/66058032381.pdfIn PDF document text
    • http://www.maderas-navarro.com/ckfinder/userfiles/files/zisafapagesamedalotoweg.pdfIn PDF document text
    • https://m-co.de/wp-content/plugins/super-forms/uploads/php/files/u6kvo4r5fauu69gl90mnhl94f4/33213789655.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/6368944b178f6ae42dc6d99bd174f4c0/suxijexizopozufipu.pdfIn PDF document text
    • http://digifast.cz/userfiles/xasexeludoxufapakir.pdfIn PDF document text
    • http://dnepropress.net/files/file/dorumoz.pdfIn PDF document text
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/clh16l9k9124hk71lj8mlk8asg/vejitibudelurimavevu.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af5dece9f43---84444210267.pdfIn PDF document text
    • http://sugarfree-gelato.com/upload/file/gagiwifepupusok.pdfIn PDF document text
    • http://svenstavik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae0a5a3e847---lezudopelen.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/caa37aad0a8d8367faa7187ffa90a70a/wofavijonofejixufipide.pdfIn PDF document text
    • https://www.truegridpaver.com/wp-content/plugins/super-forms/uploads/php/files/30a9ed74884530c310d75cbd704c180b/17266582850.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8f6db7f513.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16086ea8465ffa---wosojolusuga.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa46f7a932d---fakidugidewe.pdfIn PDF document text
    • http://nail-free.com/ckfinder/userfiles/files/tefezutep.pdfIn PDF document text
    • http://baugeraeteverleih.de/benutzerdateien/nefevi.pdfIn PDF document text
    • https://www.jahnigterbraak.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160d207e6dbad5---67627033750.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/muzalopo.pdfIn PDF document text
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/e5fb46d0b2daa0f70266d176ac250f87/jitebasodir.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_off0000cdae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDAE 17288 bytes
SHA-256: 77186a252ef91526f578b4aa53f707ee41386bc2b3c2a1f586b0adee6ad0627e
font_01_sfnt_off0000fadb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFADB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000112f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112F2 10392 bytes
SHA-256: ca9070d13fc68954f453de1d83947d80f6b21710e25ed287cf9bf490213689ad