Malicious PDF — malware analysis report

Static analysis result for SHA-256 bb257674466d5669…

MALICIOUS

PDF

85.2 KB Created: 2021-09-06 11:51:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 31d4b104152689a352a49dcd2014d735 SHA-1: 475438db4a6342ad26b17079ba79cd859c4765d3 SHA-256: bb257674466d56691092e9f49a83144ebcd74a8c528c2567293ac3f63833a95d
156 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 trojan. Static analysis revealed it functions as a link farm, containing numerous URLs pointing to other PDF files hosted on various domains, some of which appear to be compromised CMS uploads. The presence of external URI heuristics and the 'PDF_SEO_DISPOSABLE_LINK_FARM' rule indicate a deliberate effort to create a network of links, likely for malicious redirection or SEO poisoning. No scripts were extracted, but the overall structure and URL patterns suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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://hyundaidongdo3s.com/images/files/xotidoxojulexurimerubetox.pdf In PDF document text
    • http://angeladaniel.eu/uploads/files/92240183832.pdfIn PDF document text
    • https://primewestelectrical.com/wp-content/plugins/super-forms/uploads/php/files/b9fcf884033440eead596c553c69c64e/nefuliwesa.pdfIn PDF document text
    • http://cropscipublisher.com/files/upfiles/file/defoxosoviwofelexux.pdfIn PDF document text
    • http://erbilsunhotel.com/wp-content/plugins/super-forms/uploads/php/files/i28gc0ephempi80o29ojo24mb3/furofovibetef.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608cfcab4b74f---52650282567.pdfIn PDF document text
    • http://gzky.cn/dubeite/ckfinder/userfiles/files/20210807_115014.pdfIn PDF document text
    • http://fuzoku-kyujin.jp/ckfinder/userfiles/files/pudanilabolomur.pdfIn PDF document text
    • http://uk-finansist.ru/userfiles/file/77753514962.pdfIn PDF document text
    • https://mfdesign.hu/files/file/44005754978.pdfIn PDF document text
    • https://samiznojmo.cz/wp-content/plugins/super-forms/uploads/php/files/889b3c956e93d24a079dad5214c19c49/feguguwo.pdfIn PDF document text
    • http://naoshima-tours.com/images/blog//file/rowew.pdfIn PDF document text
    • http://generale-bureautique.fr/gdb/files/file/sovesesowutatoxibudiduxi.pdfIn PDF document text
    • https://www.benkorner.nl/admin/library/ckfinder/userfiles/files/12474462220.pdfIn PDF document text
    • https://www.glasswindowequipment.com/wp-content/plugins/super-forms/uploads/php/files/c72673a6050e51a2be63cc614dde9b00/totojosoxenekifusupi.pdfIn PDF document text
    • http://toyteepee.com/uploadfiles/file/210704042626192005k49r15.pdfIn PDF document text
    • http://cestovni-postylka.eu/userfiles/file/75685983465.pdfIn PDF document text
    • http://salt17.com/userfiles/files/38883380324.pdfIn PDF document text
    • http://bluefield1966.com/clients/26642/File/33652224561.pdfIn PDF document text
    • http://nbpcpentecostalchurch.com/clients/65183/File/pixofil.pdfIn PDF document text
    • https://bataretak.com/img/files/file/razamudojujazajofiles.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=vector+projection+problems+pdfPDF 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_off0000e1fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1FA 20316 bytes
SHA-256: e7d6d9888a9f04b7db33c332420b902586717590b51a3d2c51484b2c8c0d1376
font_01_sfnt_off00011710.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11710 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012f27.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F27 10860 bytes
SHA-256: a19b1aab31b8c4eb7a22d977eacc698e8be8bbaca5bb9b91a08ee01d1a3170c2

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