Malicious PDF — malware analysis report

Static analysis result for SHA-256 c90d963e880aaafd…

MALICIOUS

PDF

78.3 KB Created: 2021-06-26 12:46:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 52b1824a097a60803d73d3aceca988de SHA-1: 1381d399092774e15211cf1deab0e4b3befe17f2 SHA-256: c90d963e880aaafd5fb51b684ff1c8227e5260af8b2f825e5ff2f7257bd92f20
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to redirect users. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware delivery. No scripts were extracted, but the PDF structure itself is weaponized to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://cructi.ru/uplcv?utm_term=chapter+5+extra+practice+lesson+5.1+answers
    • https://yingzhaoliuart.com/upload/file/takuwonikedoje.pdf
    • http://shmountaineering.co.uk/wp-content/plugins/super-forms/uploads/php/files/b2gmh3j724usj0plmg9624da06/zumejugikedarosujo.pdf
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f73c5b716d---tebig.pdf
    • https://muzeumkonstancina.pl/attachments/file/jepexome.pdf
    • https://djhelaly.com/wp-content/plugins/super-forms/uploads/php/files/2892d8fd9291f3dd132909a27d5d3e09/25976314727.pdf
    • https://mamo-tato.ro/userfiles/file/3966955101.pdf
    • http://bandenplaats.nl/cmsimages/file/52081720817.pdf
    • https://claphamjunction.com.au/wp-content/plugins/super-forms/uploads/php/files/8a9dd0b838f355fac94f79bb863136d6/91571686983.pdf
    • http://supermarketdv.ru/files/file/nesarovifetamubesazenigun.pdf
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca378ef86a---4072805645.pdf
    • http://dangkykinhdoanhkiengiang.com/upload/ck/files/wumakiram.pdf
    • https://centrosteadycam.it/wp-content/plugins/super-forms/uploads/php/files/9311cf253beb4cf0328f01617c0450ac/xejujumizovokejeranibaz.pdf
    • https://betonwerkendejonge.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1606eb1e082fe4---99321081909.pdf
    • http://amghanoi.com/images/ckeditor/files/sizezalofuza.pdf
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf206c9d4c8---17230813443.pdf
    • https://gradeagroup.com/wp-content/plugins/super-forms/uploads/php/files/jh1fbv89b1msqemtkaduouhhft/90721363019.pdf
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b807b933e6f---31316772405.pdf
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a2de84d03de---fesudarajejunofigewuk.pdf
    • https://bangprice.com/bangprice.com/beta/cms_image/file/kuvazaditaraw.pdf
    • https://addsfly.com/userfiles/file/53747160523.pdf
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c63be71488f---zevosetugulerezigogovoz.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cfd2.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xCFD2 16792 bytes
font_01_sfnt_off0000e7e9.bin
2ca4bf80170cc457dd5cb0f68aefc6d23a75fbbcf295e61789af0424915ef2fc
pdf-font-stream PDF embedded font (sfnt) at offset 0xE7E9 10944 bytes
font_02_sfnt_off00010167.bin
42afb6a3a452e8422b4a579b0f922639eb0c3b9b4e43bfca25b0b42a8ba84448
pdf-font-stream PDF embedded font (sfnt) at offset 0x10167 16664 bytes