Malicious PDF — malware analysis report

Static analysis result for SHA-256 1f81319f7fdc7db9…

MALICIOUS

PDF

73.9 KB Created: 2021-09-06 20:14:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 6f8b7f6f1dc45a9f3d7388a213de2a91 SHA-1: 286a3a95135bacf077b389feed9da3f968941638 SHA-256: 1f81319f7fdc7db9bf592e2a5127ae11ccd9827326bbbfbdc831eb0c372cfcf5
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites hosting PDF files. Heuristics indicate this is a link farm designed to direct users to potentially malicious content, as confirmed by ClamAV detection as Pdf.Phishing.Trojan. The ML classifier also strongly flagged this PDF as malicious. The primary attack pattern involves luring users via a spearphishing attachment to click on these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 6

  • 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 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 http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d1e0ebddae---najidumugasozokuti.pdf In PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/pa2juqe3jdb67b5o6vmqshk2c7/robojovosiwimoniwuxenexof.pdfIn PDF document text
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b9f032a9eaa---35863281976.pdfIn PDF document text
    • https://www.ideaklinik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607dffd487b37---lanomupow.pdfIn PDF document text
    • http://vin-baietii.ro/ckfinder/userfiles/files/66624996331.pdfIn PDF document text
    • http://brcassociati.com/userfiles/files/70553032973.pdfIn PDF document text
    • https://attackworkoutprogram.com/app/webroot/files/ckfinder/userfiles/files/sazadonagasap.pdfIn PDF document text
    • https://reifenscho.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606d2d8a92e3c---30983806895.pdfIn PDF document text
    • http://johndanton.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/folebij.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/m0t3i80sjqp8mmg90t1q7568fs/23164422058.pdfIn PDF document text
    • http://klhl.com/userfiles/file/kawexoxuzisapozufim.pdfIn PDF document text
    • http://hotelniagararimini.eu/userfiles/files/83710820491.pdfIn PDF document text
    • http://rockycheng.com/ckfinder/userfiles/files/67937810112.pdfIn PDF document text
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d54c09cbe5---rarabitigu.pdfIn PDF document text
    • http://asja-doll.ru/userfiles/file/78784279740.pdfIn PDF document text
    • https://agronlogistics.com/userfiles/files/zifaz.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1612a8860897d8---rawobolodu.pdfIn PDF document text
    • https://paradigma.bg/uf/file/27056000346.pdfIn PDF document text
    • https://www.kunapak.com/wp-content/plugins/super-forms/uploads/php/files/ls4bbthcskpp7tjq5h0no1aiej/mozekuvetuxoz.pdfIn PDF document text
    • http://k12kos.com/ckfinder/userfiles/files/virijowujoboduvotu.pdfIn PDF document text
    • http://archiwum.wyryki.eu/admin/ckfinder/userfiles/files/jokafimubogoporapezubegol.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16079c4006afa3---81818377653.pdfIn PDF document text
    • https://cspdental.com/wp-content/plugins/super-forms/uploads/php/files/336009d78969e21fa37db5294b7e3645/94985831285.pdfIn PDF document text
    • http://gryfarmerskie.pl/pliki_wyswig/files/28025502744.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=irregular+verbs+present+tense+pdfPDF 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_off0000bb0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB0F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d326.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD326 10716 bytes
SHA-256: 1ac30a67b18977f0048c47b1ba0535cc509f1a894a3c9da0e9b57fec213afdbc
font_02_sfnt_off0000eb80.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB80 17952 bytes
SHA-256: 9ae65aa8751a9d2b05b064db00cebc3d18768c3a07a67f258e467355d69d63ca

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