Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4ab91e61bbd5d68…

MALICIOUS

PDF

89.4 KB Created: 2021-07-09 19:57:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 4d83582464904f6fe7071a4c0149455d SHA-1: 959b8d25f6c71fe31a865a06bf98c37a940ae89d SHA-256: b4ab91e61bbd5d68e5acba5562ddd5b5f72ed2d8d8a1659f02fe261c2d13d3eb
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating it likely exploits a vulnerability for client execution. The file functions as a link farm, containing numerous URLs pointing to compromised WordPress upload directories and other disposable hosting, suggesting an attempt to redirect users to malicious content. The presence of external URIs and link farm heuristics strongly supports this attack pattern.

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://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160d6f017cd422---zatefulejokom.pdf In PDF document text
    • http://nensi.si/upload/file/kodasejopogazazipedozis.pdfIn PDF document text
    • https://www.arc-welding.co.uk/wp-content/plugins/super-forms/uploads/php/files/408ha5uvrd84haifvdq2cdqsam/taneneratu.pdfIn PDF document text
    • https://holzhaus-suedtirol.it/wp-content/plugins/formcraft/file-upload/server/content/files/1607d5b583ab95---53047241093.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1609a424138028---76087175832.pdfIn PDF document text
    • https://www.mercedesbenzofaustinservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cd75a64d10---widamekisuzewawagowaja.pdfIn PDF document text
    • http://elcampoeco.org/FCKeditor/file/77496100885.pdfIn PDF document text
    • https://www.freshstartdigitalmarketing.com/wp-content/plugins/super-forms/uploads/php/files/9485540b23d1fa617373efc0a3b9c384/75330728820.pdfIn PDF document text
    • http://dptour.net/bot/ckfinder/uf/files/81010840499.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/p2u460b55d17gg0aduhr6ih3q1/8614572270.pdfIn PDF document text
    • http://atut-biuro.com/uploaded/file/60566303517.pdfIn PDF document text
    • http://xn----8sbxab3abskk3a2j.xn--p1ai/media/file/kakifonatakebubuvowuz.pdfIn PDF document text
    • https://qualitycountscleaning.com/wp-content/plugins/super-forms/uploads/php/files/1c4ee72b65a71ee2c2fce694f013a67c/32596957094.pdfIn PDF document text
    • https://hsegroup.ru/wp-content/plugins/super-forms/uploads/php/files/62anpr9r4fp99ikjqtghtciit2/20019590041.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b06b2861d9e---numumamerapinenir.pdfIn PDF document text
    • http://come2menorca.com/images/file/vagojereseweti.pdfIn PDF document text
    • http://speckrepeg.by/UserFiles/files/93443412733.pdfIn PDF document text
    • http://nuraski.pl/wsg/userfiles/mitutiwekofikir.pdfIn PDF document text
    • https://blsautomation.com/ckfinder/userfiles/files/rapafibife.pdfIn PDF document text
    • http://kleinschaden.expert/userfiles/file/totododu.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608524596366f---86520890087.pdfIn PDF document text
    • http://talleresjpg.es/img/file/roxametegatoxazas.pdfIn PDF document text
    • https://esz.jp/img/editor/files/6223814584.pdfIn PDF document text
    • http://rollfactorytogo.com/uploads/files/jexegoz.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/1ad061891d74864aad1075320f5f02c4/73203592553.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=southern+coleslaw+dressingPDF 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_off0000f75f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF75F 17592 bytes
SHA-256: 13959dc1903714e484514ab7cdcc9d0563f5c63188d978f5f2ec511da568b974
font_01_sfnt_off0001259e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1259E 10912 bytes
SHA-256: 5efcb8d2144fea7f27e283c828d66fe65c64377a4c128e75e8f7864b97d23c56
font_02_sfnt_off00013eac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13EAC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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