Malicious PDF — malware analysis report

Static analysis result for SHA-256 257a4a3f9edb7d9b…

MALICIOUS

PDF

81.7 KB Created: 2021-09-08 01:29:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 81b78f14b163abe707941b218738909b SHA-1: 458f4b4544d5942565acb5cacb4e2598f172fc98 SHA-256: 257a4a3f9edb7d9b6363c4ad578d425acfa4eb046985fa88391d026c3b86a3f1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was identified as malicious by ClamAV and an ML classifier. Static analysis revealed it functions as a link farm, with numerous URLs pointing to compromised WordPress upload directories. These links likely serve as lures for phishing attacks or to distribute further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://www.ashtralmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608043c09a47b---guxokojunibiki.pdf In PDF document text
    • https://www.abrasco.org.br/ckfinder/userfiles/files/kugetite.pdfIn PDF document text
    • https://bilbox.es/wp-content/plugins/super-forms/uploads/php/files/d1bf3a1ccbcceacc4283a67d12cdb75f/6990482400.pdfIn PDF document text
    • http://tchid.net/userfiles/file/linisuronaxelafabu.pdfIn PDF document text
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/pc2dhej9tosesb5it6f52l73n5/sojazarukenozuwusopatozuj.pdfIn PDF document text
    • http://hydrem.ru/images/file/kijafenig.pdfIn PDF document text
    • https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/955566e9231f84640f698e74bd2cddec/bofumuwovovozemiru.pdfIn PDF document text
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f3e228359f---47407551302.pdfIn PDF document text
    • http://targdenunti.ro/userfiles/file/96303068661.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/160d5c329af730---teropega.pdfIn PDF document text
    • https://doitsolutions.co/wp-content/plugins/super-forms/uploads/php/files/2870ede6e3ef65ec1f8dfea3f17aaaa1/30629773336.pdfIn PDF document text
    • http://fmi.lu/userfiles/files/39643740207.pdfIn PDF document text
    • https://macauroommate.com/ckfinder/userfiles/files/40589607457.pdfIn PDF document text
    • https://netiko.ge/img/Data/file/xedobexufufidajasudew.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/detatepuramotipefa.pdfIn PDF document text
    • http://abimobiliare.pl/pliki/File/fevor.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/5fjoo94r3eodmleg0mc6e8csrd/vepumijavivova.pdfIn PDF document text
    • http://bjaimama.com/data/upload/2021/05/file/202105151224154312.pdfIn PDF document text
    • https://catherinehourihan.art/wp-content/plugins/super-forms/uploads/php/files/4dc83f52a73de189062be5a624df5011/pakaxusozutefumerokegovez.pdfIn PDF document text
    • https://securitydm.net/slicice/file/zakafedadopejese.pdfIn PDF document text
    • http://rubivina.com/Images_upload/files/gojob.pdfIn PDF document text
    • https://0a3exp.com/upfiles/editor/files/17513414987.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=excel+vba+copy+worksheet+range+to+arrayPDF link annotation
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/fd77bd657308b37424c14b527c19c49d/batapele.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_off0000d75c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD75C 18268 bytes
SHA-256: dc38ca60aca2e7cc51c56d454d4646853711ce5e8fee263c31f25e6b08276170
font_01_sfnt_off000106aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106AA 11144 bytes
SHA-256: 01d210c4609cf1dda3f96db376e04b0fd7cf58df41e9c2ba281cd22141de3601
font_02_sfnt_off000120a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1