Malicious PDF — malware analysis report

Static analysis result for SHA-256 71bbb58ccb4de862…

MALICIOUS

PDF

82.3 KB Created: 2021-09-04 01:29:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 63b52eca2a88a6d103f0961722349534 SHA-1: de9e5a938f2b050c4558d0c9b43cc85f13272f0a SHA-256: 71bbb58ccb4de86207ce96cb10baa968fc4c05d47b59632510f26c96f2efc62e
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing attempt impersonating Facebook. It contains a link farm pointing to compromised WordPress uploads and other disposable hosting, with a primary lure URL at https://crewmak.ru/uplcv?utm_term=professions+in+spanish+worksheet. The document body is heavily obfuscated, preventing a clear understanding of its direct content, but the heuristics strongly indicate a credential phishing campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://crewmak.ru/uplcv?utm_term=professions+in+spanish+worksheet.
  • 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://crewmak.ru/uplcv?utm_term=professions+in+spanish+worksheet PDF link annotation
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c93e662d16d---rawab.pdfIn PDF document text
    • https://groupekheidri.com/ckfinder/userfiles/files/84585348648.pdfIn PDF document text
    • http://artechq8.com/beta/uploads/files/liworusejixolosabisux.pdfIn PDF document text
    • http://corising.info/sa_upload/userfiles/file/20210810233100.pdfIn PDF document text
    • http://moto-bike.pl/userfiles/file/48098012840.pdfIn PDF document text
    • https://sahyadrisevasanstha.in/userfiles/file/72267168748.pdfIn PDF document text
    • http://www.primalegal.eu/wp-content/plugins/super-forms/uploads/php/files/jqv8lfkrvnibpkonpjgfimrmd0/nukurewedagise.pdfIn PDF document text
    • https://esteticarcare.com/wp-content/plugins/super-forms/uploads/php/files/8aa318e5942f87048caf8b8448cf4a2c/73231068642.pdfIn PDF document text
    • https://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b0b0b43963f---zufevowuxozewesapujo.pdfIn PDF document text
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a58f7cb743e---80821926167.pdfIn PDF document text
    • http://dnepropress.net/files/file/vatezobim.pdfIn PDF document text
    • http://in-dapt.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607674ac30657---32781395699.pdfIn PDF document text
    • https://yssnewlessons.org/UserFilesTwo/file/75191364075.pdfIn PDF document text
    • http://ceresasrl.it/userfiles/files/xasur.pdfIn PDF document text
    • http://zaragozalawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/28230693006.pdfIn PDF document text
    • http://katyababash.com/images/uploads/file/27542912624.pdfIn PDF document text
    • http://ana-jsc.com/upload/files/refexijevawo.pdfIn PDF document text
    • http://3gr-group.com/ci/userfiles/files/51298186911.pdfIn PDF document text
    • http://renovfab-menuiserie.com/userfiles/file/tususeg.pdfIn PDF document text
    • https://latework.cz/soubory/nifazitogemajejixuza.pdfIn PDF document text
    • http://sh8ke.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a662c51bc3e---25572295030.pdfIn PDF document text
    • http://monarchiaerembolt.hu/tmp/97141392831.pdfIn PDF document text
    • https://carpanea.it/wp-content/plugins/super-forms/uploads/php/files/35fc080000f3c12f74314c2dcaf899d9/nefifezaxuvadures.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_off0000d891.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD891 19896 bytes
SHA-256: 84353807eec75636b4abd2d6a5be6fba00788aa4f7209c96e66fff3ee95a0cfc
font_01_sfnt_off00010b5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B5D 10588 bytes
SHA-256: 1430873f420b04544f26f1a35525240ec294c87ae907426d1b864f01507b720d
font_02_sfnt_off00012396.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12396 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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