Malicious PDF — malware analysis report

Static analysis result for SHA-256 66f4acfe5518abc4…

MALICIOUS

PDF

83.9 KB Created: 2021-08-12 13:32:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 6d4acab5c988291316d780b152248e54 SHA-1: 9bfeabea0db38a08db009e2d18d0179e2ff231dd SHA-256: 66f4acfe5518abc4b261b510ba968299bc59f957cde6dc557c4afbed1a86bf06
96 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm designed to manipulate search engine rankings or distribute malicious content. The ML classifier strongly indicated maliciousness, and the structure aligns with techniques used to obscure malicious URLs or host further stages of an attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://chcial.ru/uplcv?utm_term=10+ejercicios+de+ley+de+signos+resueltos PDF link annotation
    • http://capri.lt/userfiles/files/tawujeni.pdfIn PDF document text
    • http://kulturazebrak.cz/userfiles/87693815125.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1610bedb1e1971---dutati.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16093f47e769f7---8906267751.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075ef0988175---70653533248.pdfIn PDF document text
    • https://minipowerpack.net/upload/files/10343064622.pdfIn PDF document text
    • http://giovanniseneca.eu/userfiles/files/68839830849.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16111f065cbd36---1547483970.pdfIn PDF document text
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ddce9c7acf8---93805225374.pdfIn PDF document text
    • http://abwmercury.com/uploads/files/gapuzidefotagagumado.pdfIn PDF document text
    • http://hainescentreasia.com/images/file/motusuz.pdfIn PDF document text
    • https://dodatnagarancija.com/userfiles/file/8429001549.pdfIn PDF document text
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/c4173d9cbe36473bcfde6391de809e21/96303983018.pdfIn PDF document text
    • http://riverla.vn/uploads/userfiles/file/tabotej.pdfIn PDF document text
    • http://cokhiminhhien.com/media/ftp/file/6552968998.pdfIn PDF document text
    • https://theatresaucinema.fr/uploads/file/45580495405.pdfIn PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/edq5qvl6me7hahr387i0co31i4/46780827015.pdfIn PDF document text
    • http://klimatyzacjaradom.pl/userfiles/file/xejudawujaji.pdfIn PDF document text
    • http://xn----7sbezcba9a5aggb3j.xn--p1ai/ckfinder/userfiles/files/26553180437.pdfIn PDF document text
    • http://pebyte.com/wp-content/plugins/super-forms/uploads/php/files/m61e5f7ngvcf301cu7k3kssh31/98482012564.pdfIn PDF document text
    • https://ruiguoex.com/upfile/files/2021/06/03/33947514866.pdfIn PDF document text
    • http://sanxuatbanthinghiem.org/app/webroot/uploads/files/mujubuxinaworazatiku.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f7d3fded26---38000654908.pdfIn PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16098dece7bbcc---laxubuwuxuv.pdfIn PDF document text
    • https://www.mysmilestudios.com/wp-content/plugins/super-forms/uploads/php/files/d4f3be2f71f09e5983bdb0ea7194080a/74256979051.pdfIn PDF document text
    • https://relaxationplusmn.com/wp-content/plugins/super-forms/uploads/php/files/ea72880f6fa28bf3efadf37d39fd774e/xafikiduterabenedexete.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_off0000e262.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE262 17488 bytes
SHA-256: 4750d7a471e5ea83a24525ca4d8cc2f02066ef69a9a70eab7af6417fd0c67903
font_01_sfnt_off00010eae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EAE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000126c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126C5 10804 bytes
SHA-256: 9c93f7811bd88cf0969c5e45df3562e184a283557b0a074ed19b5c651a9376fc