Malicious PDF — malware analysis report

Static analysis result for SHA-256 535d72238833f8be…

MALICIOUS

PDF

94.3 KB Created: 2021-07-06 00:26:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: 29c12319f87ff4a4b4c10c9f68b6038f SHA-1: f0a87e8e456413e3c499588a33c1a66a3baa1189 SHA-256: 535d72238833f8bec7b3ebcfd8f63a9c0d247eaded518a667847d2b3ee5b12ff
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF was flagged by ML classifiers and ClamAV as malicious, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to compromised CMS upload directories or disposable hosting, suggesting it functions as a link farm to distribute further malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://airflow-skateboards.com/upload/file/zivonis.pdf In PDF document text
    • https://aydin-elektrik.com/resimler/files/suwavefijobakamimori.pdfIn PDF document text
    • https://gmonlinestore.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d348580f356---sakute.pdfIn PDF document text
    • https://www.icslights.com/wp-content/plugins/super-forms/uploads/php/files/15cc4ae49a93e9e0e426791433d580cf/24985733999.pdfIn PDF document text
    • https://protechlighting.com/wp-content/plugins/super-forms/uploads/php/files/962a548ab7329dab196128fd9738b59c/68633689764.pdfIn PDF document text
    • https://www.baptistenhardenberg.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160814cf9c78ea---94683819035.pdfIn PDF document text
    • http://selfmadefilms.nl/userfiles/files/57947956887.pdfIn PDF document text
    • https://chezgregoire.fr/userfiles/19798869031.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/eb63eb0969eefffd56ca4fd8e4af142e/keburavugovidozuvoke.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16080dd1d3d629---namiti.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/cgum1vrair8h6bv84gbg0hso52/22757650921.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/9a6747898db52847edd01ec5b13e4f27/74287742824.pdfIn PDF document text
    • http://asbu.net/uploads/FCK_files/file/xigazunijufomezixotujaniz.pdfIn PDF document text
    • https://avonsteel.com/UserFiles/file/vomeri.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/frrj3k81ffc1b1ri96v2dk1vkt/60713045832.pdfIn PDF document text
    • https://www.justgym.co.za/wp-content/plugins/super-forms/uploads/php/files/v0o8klughm7fmvj6vgumranf2o/gixegugij.pdfIn PDF document text
    • http://zpkprzemysl.pl/ckfinder/userfiles/files/35058237717.pdfIn PDF document text
    • https://www.crossfitparamaribo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab4c0dac42f---37963195834.pdfIn PDF document text
    • http://fashioncenterpoint.com/wp-content/plugins/super-forms/uploads/php/files/7a0e9f67896b20b014143be7866d0f2c/14214422588.pdfIn PDF document text
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/160db7db9c63d6---86753918995.pdfIn PDF document text
    • http://yishiweb.com/upfiles/files/20210530_020115.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/60dd6dc9e52e3e651f2787a5b5c839f6/50384524012.pdfIn PDF document text
    • http://barbusci.it/maisUserFile/file/64496702486.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=billy+idol+youngPDF 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_off000111fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111FC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012a0e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A0E 17276 bytes
SHA-256: 7327ec14d2e8dc8f8cbd7bc18386f8a2626a27116da55507baebf3603a77f843
font_02_sfnt_off00015643.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15643 10028 bytes
SHA-256: 024e4cf599955761f3d79d8e4bdb658b49b9d6032bea885deef48e31f53153a2

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