Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb1a19643bebb6be…

MALICIOUS

PDF

84.4 KB Created: 2021-08-25 23:04:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 09416b0ef80eacd7b9a8e8eeab56ea54 SHA-1: 1020a6937a1496ebe706544f986ade8fcb64d688 SHA-256: cb1a19643bebb6bea3457c2af7695ee57b976a31ad95710e9e4d123e776fd726
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the heuristic firings and URL analysis point to a common PDF-based lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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 https://catamma.ru/uplcv?utm_term=anatomy+of+shoulder+joint+pdf PDF link annotation
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/16098fdb4dcf5d---nizitog.pdfIn PDF document text
    • https://deconkhoemanh.com/wp-content/plugins/super-forms/uploads/php/files/49b3m5qhq6pb68nb3sp44b49pm/wikamomowared.pdfIn PDF document text
    • http://kahounova.cz/userfiles/file/jawibimobipu.pdfIn PDF document text
    • http://nanouklid.cz/upload/file/dutimegaxidewozujanov.pdfIn PDF document text
    • http://www.specemc.ru/upload/files/48126137239.pdfIn PDF document text
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606d3f23d987f---tuwelapetuxovozenasuxedu.pdfIn PDF document text
    • https://www.tctnanotech.com/wp-content/plugins/super-forms/uploads/php/files/78c5026c4ad4cc39ef41645f907ab1b5/bukewu.pdfIn PDF document text
    • https://baobihungphu.com/media/ftp/file/73519150631.pdfIn PDF document text
    • http://yossy.biz/userfiles/file/46357847725.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/7a07e68c929081bd9de0cd5fc6de7f98/xemotejidedeliw.pdfIn PDF document text
    • https://arihantgranites.in/wp-content/plugins/super-forms/uploads/php/files/eju193jfiucrcib25ulkk2fvo4/91890039943.pdfIn PDF document text
    • http://ck-tct.ru/userfiles/file/limamirekone.pdfIn PDF document text
    • http://ersatzmonitor.de/userfiles/file/60564918339.pdfIn PDF document text
    • http://www.dismaplant.com/ckfinder/userfiles/files/bofuzigorabitu.pdfIn PDF document text
    • http://falegnameriacastiglione.it/userfiles/files/4548957916.pdfIn PDF document text
    • https://newat.ru/wp-content/plugins/super-forms/uploads/php/files/9601036cf3b35e7313aba305adb2d14b/59244285360.pdfIn PDF document text
    • https://subarini.ro/mm/file/43081635796.pdfIn PDF document text
    • https://twr1115.net/files/fckeditor/file/50038576915.pdfIn PDF document text
    • http://es-hanasaki.com/yamituki-n/uploads/files/nerid.pdfIn PDF document text
    • https://tselectromechanical.com/uploads/CKfiles/files/rijabakukogew.pdfIn PDF document text
    • http://provia-events.de/pics/fotos/1/file/lenefolivar.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_off0000e5e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5E5 16888 bytes
SHA-256: ef91bb7909753c04476fa79cc362286c556c31c84c985e88a38d6d086f74532d
font_01_sfnt_off000111bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111BC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000129d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129D3 11088 bytes
SHA-256: 7b4f888885dbec9f07e1f54c5d2672a44a12483feeae20b99af225dd00f86256