Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4eb126ab1761b25…

MALICIOUS

PDF

68.7 KB Created: 2021-09-27 06:42:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 97990b8b78a57122e804324e6b93fed6 SHA-1: 033f586abe1cc2e0d7c105f839323087c88cd819 SHA-256: a4eb126ab1761b2579d36beb091c3c95413afa767d12cb797d338d8ec5fe6060
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites acting as link farms. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of link farms on disposable hosting and the use of UTM parameters suggest an attempt to obscure the final destination and potentially improve search engine ranking for malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9950

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://medvor.ru/uplcv?utm_term=eye+test+android+app PDF link annotation
    • https://roofmed.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613cd80f9b85c---1439652530.pdfIn PDF document text
    • http://fanghsin.com/uploads/files/202109140059054575.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161364bc483e42---fegokawojiw.pdfIn PDF document text
    • http://bebcardkw.com/ckeditor-ckfinder-integration/uploads/files/xexara.pdfIn PDF document text
    • http://turinhotelcompany.com/userfiles/files/19390194040.pdfIn PDF document text
    • http://applecentervn.com/uploads/image/files/89330911110.pdfIn PDF document text
    • http://markasib.ru/ckfinder/userfiles/files/87754622190.pdfIn PDF document text
    • https://abrasco.org.br/ckfinder/userfiles/files/zezuxetivolesizevu.pdfIn PDF document text
    • https://rh4-h1tapi-turbo.com/contents/files/27415008702.pdfIn PDF document text
    • https://promenade-perpignan.com/userfiles/file/nosabowev.pdfIn PDF document text
    • https://hardlineconstruct.ro/app/webroot/files/userfiles/files/27765815763.pdfIn PDF document text
    • http://toptoptraining.ru/img/upload/file/69014652579.pdfIn PDF document text
    • http://0048.pl/48files/file/65911725507.pdfIn PDF document text
    • http://szermgrt.hu/uploads/ckfinder/userfiles/files/35089899995.pdfIn PDF document text
    • https://ita.kru.ac.th/ckfinder/userfiles/files/kutonowet.pdfIn PDF document text
    • http://moonlightmontessori.com/upload/files/96525852282.pdfIn PDF document text
    • http://nuyewrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/42a71c12bdb014303648059267da13c0/99251059294.pdfIn PDF document text
    • http://oguzlarotomatiksanziman.com/depo/sayfaresim/file/xugamajasizi.pdfIn PDF document text
    • https://www.educationsexuelle-ecole.ch/ck/ckfinder/userfiles/files/50367840662.pdfIn PDF document text
    • https://steammining.com/userfiles/file/zezetojodejalumusudoxo.pdfIn PDF document text
    • http://www.cavice.fi/tiedostot/files/bonefibisuv.pdfIn PDF document text
    • https://we-plus.tw/ckfinder/userfiles/files/22241317301.pdfIn PDF document text
    • http://lalitas-thaimassage-spa.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614013bc9d118---73086103684.pdfIn PDF document text
    • http://yulintimber.cn/d/files/37272795519.pdfIn PDF document text
    • https://ncltandatbar.com/home/ncltandat/public_html/dowalumniusa/ckfinder/userfiles/files/nekexaf.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_off0000af7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF7F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c796.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC796 10436 bytes
SHA-256: 6ba63af7db363f4208b599555a743482534f93a4e178e7550f19022a8ece3186
font_02_sfnt_off0000df66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF66 15388 bytes
SHA-256: ea110a3dd8a07ab77cffa580458caf20997858c25f9cd4fd81adc0339a635401