Malicious PDF — malware analysis report

Static analysis result for SHA-256 56cf9dc8847997ff…

MALICIOUS

PDF

79.6 KB Created: 2021-09-09 06:46:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 93c36b92c579a69877c7f6c56b550dfb SHA-1: e1475daf92f4f8d2034e9a73548a684392ac5f1b SHA-256: 56cf9dc8847997ff24c9143796c43f7c0cb24609ae7d36d83e0c22931b4120f9
156 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs, many of which point to compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to redirect users to phishing or malware hosting sites. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, suggesting it's not intended for direct user interaction but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://censcakmu.org/board/file/files/zegolemifekuj.pdf In PDF document text
    • https://www.yoursurveysurveyors.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16139596437efb---3187813005.pdfIn PDF document text
    • http://nwatchonline.info/userfiles/file/fefijokesuxupod.pdfIn PDF document text
    • http://meyergarden.com/ckfinder/userfiles/files/fatonip.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/i41jtiqst2r6agso0e8dl9d0mp/petezixomadenaruvexirufuf.pdfIn PDF document text
    • https://www.bramfordgc.co.uk/ckfinder/userfiles/files/41453667422.pdfIn PDF document text
    • http://alltechsro.cz/files/55458569969.pdfIn PDF document text
    • https://floridainvestment.cz/files/file/resakemigubanovubegasena.pdfIn PDF document text
    • http://novaserv.com/wp-content/plugins/formcraft/file-upload/server/content/files/161343f4cce8e8---japusotam.pdfIn PDF document text
    • http://simoncaulkin.com/images/102620440.pdfIn PDF document text
    • https://locktactyuma.com/ckfinder/userfiles/files/tidifezogalikizanuzusaw.pdfIn PDF document text
    • http://aibasavar.edu.bd/app/webroot/ckfinder/userfiles/files/budagobetuf.pdfIn PDF document text
    • https://fiscalonline.eu/app/webroot/files/userfiles/files/53703278442.pdfIn PDF document text
    • http://dekoblickfang.de/userfiles/file/kibamudix.pdfIn PDF document text
    • http://konditsionery-reutov.ru/upload_picture/file/totikugavikotetas.pdfIn PDF document text
    • http://aktasmatbaacilik.com/resimlerfiles/wetixovodepukizadekozupel.pdfIn PDF document text
    • https://goldenparadisestsimons.com/wp-content/plugins/super-forms/uploads/php/files/670ff181c2ed14f1c6bb629002b8b384/kopefokitipede.pdfIn PDF document text
    • https://behagi.eus/files/galeria/files/57271137562.pdfIn PDF document text
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/1a50c8797578571c058dc1d20a710f74/32213240943.pdfIn PDF document text
    • http://momsystem.ru/public/file/22965434443.pdfIn PDF document text
    • http://onishi-kyosendo.jp/archive/ziniki.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/161343e1043d28---95901777313.pdfIn PDF document text
    • http://paymentsbusiness.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161392f29bb605---82887367144.pdfIn PDF document text
    • https://lashmakerpro.it/wp-content/plugins/super-forms/uploads/php/files/7h025sanpui4sgp2nj200r2bg2/33936409711.pdfIn PDF document text
    • https://xosobacninh.vn/webroot/img/files/48176132021.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=noop+vs+deadline+androidPDF 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_off0000d353.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD353 17428 bytes
SHA-256: 8db4bcf69e9dcd0eeceb8c7010c9bcc22e74ffa2923eb4f0aab8caa1ab5d8b4d
font_01_sfnt_off000100cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100CF 10332 bytes
SHA-256: abc41b6f9f17e97dd6705bd2501ee43190791661a0c4d29f03e15f759c99358b
font_02_sfnt_off00011835.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11835 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1