Malicious PDF — malware analysis report

Static analysis result for SHA-256 b23ab5b884a67dac…

MALICIOUS

PDF

69.6 KB Created: 2021-06-13 22:21:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 83e5e11c5b6f46dfae660488157ff6ec SHA-1: 8bd5cc3fd267ba2e35c104cbf0b7a2fe3c0c6946 SHA-256: b23ab5b884a67dac21ce6aee5723572e8b99cc53ae4a2205b3d1fc589065693c
196 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous links to external PDFs, many hosted on compromised WordPress sites or disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, appears to be a lure related to a 'culinary professional study guide answer key', aiming to trick users into downloading further malicious files.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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 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://crysiq.ru/uplcv?utm_term=the+culinary+professional+study+guide+answer+key PDF link annotation
    • http://globalcenterhotels.com/bot/ckfinder/uf/files/rojufef.pdfIn PDF document text
    • http://www.darvidproperty.com/news/file/63182143681.pdfIn PDF document text
    • https://munord.com/wp-content/plugins/super-forms/uploads/php/files/f0fda3aee6b422bdaba86b445883ee1d/12615176834.pdfIn PDF document text
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b377c054da---dorubu.pdfIn PDF document text
    • https://www.hinogas.com/wp-content/plugins/super-forms/uploads/php/files/al26gljtv7me26gei1kvrl69ae/92207582089.pdfIn PDF document text
    • https://www.simcoerecovery.net/wp-content/plugins/super-forms/uploads/php/files/3a49gtdvc1bkpjklms7490dsd1/9708413248.pdfIn PDF document text
    • https://www.actionconstructionjax.com/wp-content/plugins/super-forms/uploads/php/files/41ba736bb0bed766cdcd4bb85856795f/14035980671.pdfIn PDF document text
    • http://grawerlik.pl/userfiles/file/82353692243.pdfIn PDF document text
    • https://bonacorsi.it/file/4973135661.pdfIn PDF document text
    • https://www.justgym.co.za/wp-content/plugins/super-forms/uploads/php/files/qlicd241nok3382gejdtpvgf8k/80873566207.pdfIn PDF document text
    • http://ilkyoukais.com/Images/Media/files/lodigoz.pdfIn PDF document text
    • http://mmbc.cz/_data/user_files/file/1652264711.pdfIn PDF document text
    • https://drainscovers.com/wp-content/plugins/super-forms/uploads/php/files/219573374528eca7ae0da7b7d94d72ac/5907415154.pdfIn PDF document text
    • http://artistalexanderkanevskywinnerinternationalaward.com/clientMedia/file/70805752331.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160b05e2798a16---xowagenadefotosezilod.pdfIn PDF document text
    • https://victory-agency.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b22fb15c6dc---91977021217.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d366.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD366 5624 bytes
SHA-256: 0443d5aa934fb0f3c97edc790d5aa4e4924175156160b56505ecef966b0df469
font_01_sfnt_off0000e69f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE69F 10100 bytes
SHA-256: 9b647a1b870dbc71e398a7dea325bd9d9f06955d411bb92836775857003897f2