Malicious PDF — malware analysis report

Static analysis result for SHA-256 31e7c4e71f402601…

MALICIOUS

PDF

81.0 KB Created: 2021-09-05 18:57:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 63f5e4074f1dc6626c8916d10483d1f1 SHA-1: b0160aa45df939d9c0ffc0e59fce36fe07f27973 SHA-256: 31e7c4e71f4026015191c0741c3f82531d31773c3f35ffd742020ae8360f1014
156 Risk Score

Malware Insights

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

The PDF file contains a link farm with numerous URLs pointing to various websites, many of which are hosted on compromised CMS platforms or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. The presence of multiple PDF link farm heuristics confirms the document's purpose is to redirect users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://chothuexehochiminh.com/userfiles/file/65854230287.pdf In PDF document text
    • https://frasertechno.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a95776482a0---wowuroxakozibinaxil.pdfIn PDF document text
    • https://www.corridar.com/wp-content/plugins/super-forms/uploads/php/files/48ddb1mqoucsat1lmshbbl0onv/95573107436.pdfIn PDF document text
    • https://sinarwaja.com/account/files/65732588211.pdfIn PDF document text
    • http://ez-surveying.com/htdocs/cljr/data/files/zegodosegevimofa.pdfIn PDF document text
    • http://bamor.org/userfiles/file/robizaroxolegasigenus.pdfIn PDF document text
    • http://maidichike.com/upload/files/mojirotu.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/1608a4942f33f3---43565921957.pdfIn PDF document text
    • https://charqueadaboavista.com.br/wp-content/plugins/super-forms/uploads/php/files/88b067ba45f312c5c0ea6881d4e6cae5/17951616455.pdfIn PDF document text
    • http://architettoseneca.com/userfiles/files/jeduvovunufogafijad.pdfIn PDF document text
    • http://architettoseneca.com/userfiles/files/kanipoledikerovujugep.pdfIn PDF document text
    • http://usmleworkout.com/files/file/81582805888.pdfIn PDF document text
    • https://www.lucaslobker.com/minor/ckfinder/userfiles/files/13826875011.pdfIn PDF document text
    • http://hurtmar.pl/Upload/file/62774874144.pdfIn PDF document text
    • http://gazosilikatnn.ru/uploads/files/vozototaketubofajutoz.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/1612a6c32f2570---puxaxe.pdfIn PDF document text
    • http://xn--vb0b83rba554gca.kr/page_data/file/20210509125736.pdfIn PDF document text
    • http://ksnjl.com/userfiles/files/68533816495.pdfIn PDF document text
    • http://wadirumshootingstars.com/userfiles/file///pudopeku.pdfIn PDF document text
    • http://comp-art.ru/userfiles/file/rimadomegokoloridepi.pdfIn PDF document text
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a337c75f49d---69706207947.pdfIn PDF document text
    • http://jfkanacon.org/data/userfiles/files/19730446699.pdfIn PDF document text
    • http://www.saveurspoitoucharentes.com/admin/ckfinder/userfiles/files/44155041580.pdfIn PDF document text
    • http://newo.ru/files/files/39132321761.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=crossword+worksheet+maker+freePDF 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_off0000d881.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD881 17492 bytes
SHA-256: a2b7478eb32249cce02eab248906baed6dd759c4a13316e4cf857cd5c716a974
font_01_sfnt_off00010592.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10592 10584 bytes
SHA-256: 828fbaccb0153562e7d95025836510553a2c683f036546672e7f9bfd1e646ba2
font_02_sfnt_off00011de1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DE1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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