Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c613908827f2663…

MALICIOUS

PDF

94.2 KB Created: 2021-07-02 22:47:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 3bcc712c94ad7b843e4150111bdf405e SHA-1: 068ac4465620c2c2acb96722d47a49b1b4c93343 SHA-256: 4c613908827f2663d4baa922a0b944c10f8a10bb00d0e4fb3b342f9d04ace3b1
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to compromised CMS upload directories, suggesting it's used to distribute further malicious content or phish users. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://novaserv.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070863ad5dd3---xelopozipugujuriwoxeb.pdf In PDF document text
    • https://thehamptonsbloomington.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077f936e4194---34826801485.pdfIn PDF document text
    • http://www.contectrade.hu/fckfiles/file/tutedosudovofobetovojo.pdfIn PDF document text
    • http://eduomania.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c988bb961f9---92112037148.pdfIn PDF document text
    • https://www.helpfulhunks.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608611c55e594---17253675814.pdfIn PDF document text
    • https://specialbrands.gr/wp-content/plugins/super-forms/uploads/php/files/3c2cba7d25e6a3b0ddb7e79bf492660d/vexiritufuranu.pdfIn PDF document text
    • https://abhimaninteriors.com/ckfinder/userfiles/files/7552958797.pdfIn PDF document text
    • https://www.sharpeningfactory.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c24972b4c7a---56464112688.pdfIn PDF document text
    • http://abwmarlboropike.com/uploads/files/93637220293.pdfIn PDF document text
    • http://wypelnienia.kratex.pl/wp-content/plugins/super-forms/uploads/php/files/093385d63ba372cce714fc0825772efb/suduva.pdfIn PDF document text
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e5ad562a8a---89071100903.pdfIn PDF document text
    • https://alarouba.com/ckfinder/userfiles/files/8497893723.pdfIn PDF document text
    • https://www.businesswatchguardingservices.co.uk/wp-content/plugins/super-forms/uploads/php/files/149ml7gn78br903uvm7l7a5iqh/xuxuvexasirasugexiwig.pdfIn PDF document text
    • http://global-gypsum.com/wp-content/plugins/formcraft/file-upload/server/content/files/160adafab51f5b---kapasavusokume.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c618756e99a---sagotulugif.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/090629ccd8dd401010b08a1dc1d13ecd/vopigatesabunofasus.pdfIn PDF document text
    • http://itaindustrial.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c8d5f8a700a---kojipuniwidirabuwanuf.pdfIn PDF document text
    • http://tzoetemondje.be/uploads/files/sagalogevegibafuzusadu.pdfIn PDF document text
    • https://www.lang-mayer.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608888d466908---kezifatolutefitobeviga.pdfIn PDF document text
    • https://heritagecambodiatravel.com/userfiles/file/wijuparewuzikexu.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/16095c13ea5d67---68204421992.pdfIn PDF document text
    • https://a2designbg.com/userfiles/file/72049460405.pdfIn PDF document text
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d4849aee9e---32050098783.pdfIn PDF document text
    • https://houstoncoinshow.org/FCKeditor/file/4650136929.pdfIn PDF document text
    • http://goteneplast.se/files/images/file/fexulapemiwajojekukelep.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=best+topless+beaches+in+the+worldPDF 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_off00010c22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C22 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012439.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12439 10892 bytes
SHA-256: f2902db03ff53dac617ce755cd95ff314933af7aaf00236fcf1c0ebf46b50f91
font_02_sfnt_off00013d40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13D40 17272 bytes
SHA-256: cd02693297f34cfb9acfdbdbdc1b91d4cc96a05324033895f1e1375ac22ca96b