Malicious PDF — malware analysis report

Static analysis result for SHA-256 857e3e637bd97de4…

MALICIOUS

PDF

75.5 KB Created: 2021-08-05 01:02:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 70cacf80cb6a6dfe8b4e542470d2d12b SHA-1: b3e3712fde08285673e4286699377774c5b38e2e SHA-256: 857e3e637bd97de4c8ad23fd36a5d2335bd59767e014cc211799718184fa6f15
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains numerous embedded links, many of which point to compromised CMS upload directories or disposable hosting, indicating a likely phishing or malware distribution attempt. The ML classifier strongly flagged this PDF as malicious. While no scripts were directly extracted, the heuristic firings suggest the document's primary function is to redirect users to malicious URLs, aligning with spearphishing tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

Heuristics 6

  • 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://krisoc.ru/uplcv?utm_term=descargar+metodo+suzuki+piano+pdf PDF link annotation
    • http://veivel.com/userfiles/file/nizusilabupib.pdfIn PDF document text
    • http://srilakshmienterprises.net/uploads/zobaxitirem.pdfIn PDF document text
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b344dc99764---bifininewiforapomevewu.pdfIn PDF document text
    • https://alakharia.com/public_html/userfiles/file/44388181728.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/bdhibvc8tkp62u1mmuv6l3fos5/61707145530.pdfIn PDF document text
    • http://hertzlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/pemodu.pdfIn PDF document text
    • http://gardenofsound.com/userfiles/files/42798661894.pdfIn PDF document text
    • https://plentis.eu/ckfinder/userfiles/files/gejerad.pdfIn PDF document text
    • http://piqiso.ru/userfiles/file/novezuxedaxipotimujo.pdfIn PDF document text
    • http://project-lovcen.me/userfiles/file/87526540442.pdfIn PDF document text
    • https://nailseasupportgroup.com/wp-content/plugins/super-forms/uploads/php/files/92c64d09a365ad223f13cc64f1c7766a/xupijotivov.pdfIn PDF document text
    • http://webelievedin1984.com/clients/6/67/676624d6593aa512bfa6e10e765af00e/File/bixigekinoden.pdfIn PDF document text
    • https://prikolnaya.com/wp-content/plugins/super-forms/uploads/php/files/25bfc4dcc1bdb80c9df75cf6a9c5d8d3/97116351888.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1608f5a3c4047b---76059461275.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/160883d195dcd5---rulijabedifidaw.pdfIn PDF document text
    • https://www.gasserbush.com/wp-content/plugins/super-forms/uploads/php/files/ae3a4d3933de4f427c38d0259a601e93/61625961212.pdfIn PDF document text
    • http://booklandbooks.com/userfiles/file/75315885261.pdfIn PDF document text
    • http://ge-mak.com/files/lokojorutejijiriji.pdfIn PDF document text
    • http://idroter.org/userfiles/files/doxufikogupipasobasepib.pdfIn PDF document text
    • https://alphacleanwashing.com/wp-content/plugins/super-forms/uploads/php/files/7b1c41aa5c6f2163ff049fbfde927b8c/ximomizekitowiz.pdfIn PDF document text
    • https://www.hotwaterfactory.com.au/wp-content/plugins/super-forms/uploads/php/files/57f20bc7225497f4f75f6b10d67e6de0/22412085588.pdfIn PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b59c649cf6d---sojur.pdfIn PDF document text
    • https://mediaget.com/userfiles/files/21416636711.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_off0000c0f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC0F1 16708 bytes
SHA-256: 75688d5fdbdc715b2a7c7b3e1530437ad17dc158dc0c1bd6c954c7f1c94d12eb
font_01_sfnt_off0000eb68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB68 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001037f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1037F 11172 bytes
SHA-256: 7e7eb09a6fefe1c6ab80d05d5de6a2771f9e20fba52b0c750c616023d05b1e75

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