Malicious PDF — malware analysis report

Static analysis result for SHA-256 8537fd4515f1489f…

MALICIOUS

PDF

77.6 KB Created: 2021-09-05 09:10:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 0690b314a1482b1358b14fc8744d7bf0 SHA-1: 3a3ebd8b0257ddab9e38b801722ce161cf1b679f SHA-256: 8537fd4515f1489fd78448bdf9aaea093324a6f561b7a6d7a61b28b3ffd5d072
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple compromised websites hosted on disposable infrastructure. While no scripts were explicitly extracted, the PDF structure and link farm behavior suggest an attempt to redirect users to malicious content, likely for phishing or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1607bb0e8ce499---rididemuvupiwirabavoboxat.pdf In PDF document text
    • https://miamiuniquelimo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160eca9426b104---takazatimunejuwopu.pdfIn PDF document text
    • http://sugarfree-gelato.com/upload/file/28577078172.pdfIn PDF document text
    • https://pasarant0g3l-turbo-h1t.com/contents//files/relujowosimolesu.pdfIn PDF document text
    • http://rjt1.org/upload/files/poluponod.pdfIn PDF document text
    • https://envida-nieuws.nl/bsb_website/upload_fck/file/22261917233.pdfIn PDF document text
    • http://silver.jo/ckfinder/blanc/files/16303414936.pdfIn PDF document text
    • https://www.rydalmereprestige.com.au/wp-content/plugins/super-forms/uploads/php/files/5ac1aq2e8li84gfev7jtlojoo9/84972605791.pdfIn PDF document text
    • https://yaslibakicisi.net/userfiles/file/wikixe.pdfIn PDF document text
    • https://www.golaw.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607f0d21a3db1---lanejojuvawasagan.pdfIn PDF document text
    • http://alliance-ltd.com/userfiles/mokasak.pdfIn PDF document text
    • https://oilbasaro.com/web/images/ckfinder/files/20210702121645.pdfIn PDF document text
    • https://seataclightingalaska.com/wp-content/plugins/super-forms/uploads/php/files/1475eb31bc4e3ed12e7d1c862b088d53/52193168963.pdfIn PDF document text
    • http://divapharma.com/uploaded/file/16747284136.pdfIn PDF document text
    • http://la-roofers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607e0ab002503---pegevegun.pdfIn PDF document text
    • http://kagoshimakojintaxi.com/userfiles/file/67968334774.pdfIn PDF document text
    • https://kvgrup.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/1609a9c4e8727b---18803179355.pdfIn PDF document text
    • http://vinmexindia.com/uploads/bejupabozezix.pdfIn PDF document text
    • https://thealloywheelcentre.co.uk/wp-content/plugins/super-forms/uploads/php/files/e1846296db65021abf86be471133fc86/rovotiroxaf.pdfIn PDF document text
    • http://eksan-ltd.com/userfiles/file/fopogigelojudiwofurix.pdfIn PDF document text
    • http://test.uebersetzungen-nesselberger.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b757111e74d---76776584407.pdfIn PDF document text
    • http://poorclarescork.ie/images/lonebilebizotoj.pdfIn PDF document text
    • https://fortlauderdale-carservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160944bdbef28f---nekopodajuxasototeji.pdfIn PDF document text
    • https://gccpay.net/wp-content/plugins/super-forms/uploads/php/files/c67c05b80aa7d96de91efbec9cd2b987/36321498597.pdfIn PDF document text
    • https://beysukonaklari.com/ckfinder/userfiles/files/nugoxororelaweduse.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=english+grammar+exercises+conditionals+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_off0000ca1c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA1C 17216 bytes
SHA-256: df6d3ff989f9031e9e64a250b1ae407b8bccaafe4df30ad6681146ec1e617e4e
font_01_sfnt_off0000f6bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6BC 11152 bytes
SHA-256: 86b0fdcb6c797653906724f0089d7c7f862808672e7feae3eb2d2a26c907abe9
font_02_sfnt_off00011064.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11064 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1