Malicious PDF — malware analysis report

Static analysis result for SHA-256 c1dca422dbf76107…

MALICIOUS

PDF

113.7 KB Created: 2021-08-17 08:18:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 26159734173c6c68e442cd0d0fa042b5 SHA-1: d7e08828dd67cb91fcdc159abdfa7b7c7aeea5de SHA-256: c1dca422dbf76107022d010bc6d2fffc2e0a5351fe163a7b1a40f6dd16d1fa92
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites acting as link farms. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/7c0ec9bfa6aaaaf38ac8ffe410f4f083/55301215689.pdf In PDF document text
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/avtpll007a3o28cvjrunuvbdj9/5378500430.pdfIn PDF document text
    • https://www.groupe-coelho.fr/ckfinder/userfiles/files/jomezutufodarenumaj.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160aff7089731b---9996501829.pdfIn PDF document text
    • https://alatheir.com/atheirwsfiles/file/87204258586.pdfIn PDF document text
    • http://popmetre.com/news/files/73444399798.pdfIn PDF document text
    • http://3duct.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac2e7106b70---tolelesukuke.pdfIn PDF document text
    • https://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/3d18c4fbd5cb22a20e225532858bb131/lujuj.pdfIn PDF document text
    • http://cesurmakina.com/userfiles/file/73451434476.pdfIn PDF document text
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f8e5ce1505---36052394249.pdfIn PDF document text
    • http://highspiritsmusic.com/ckfinder/userfiles/files/75828403591.pdfIn PDF document text
    • http://hardiebase.com/uploads/assets/filefile/vasezebumobonajumu.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a45f502a2b9---wepilon.pdfIn PDF document text
    • https://ldcpc.com/ckfinder/userfiles/files/kiberixudinu.pdfIn PDF document text
    • https://penal-garazh.ru/files/83178913098.pdfIn PDF document text
    • http://pro-elec.ru/ckfinder/userfiles/files/dununijadurusegudikujib.pdfIn PDF document text
    • http://ecofincas.net/ckfinder/userfiles/files/32485968926.pdfIn PDF document text
    • https://vntdc.com/upload/fck/file/jaresevi.pdfIn PDF document text
    • http://lncxjzxxw.com/upload_fck/file/2021-6-26/20210626204637579742.pdfIn PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/16077279010f46---dulikipejolukunozore.pdfIn PDF document text
    • https://olmitek.by/wp-content/plugins/super-forms/uploads/php/files/nhp1ioqa4e94r69d2b6dbkbc95/80017466691.pdfIn PDF document text
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba198319ebc---8277773051.pdfIn PDF document text
    • http://swaving-stalinrichting.nl/ckfinder/userfiles/files/53229422272.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/160d26955f260d---57239620175.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=writing+task+2+ielts+academic+topics+2020PDF 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_off0001582d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1582D 11184 bytes
SHA-256: 767d9e351fcd9457b058737b697176488afa8647345e28f1b9721cdd5fc86632
font_01_sfnt_off00017226.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17226 16940 bytes
SHA-256: 3e879b664103c57cf020f80cfe3a418ea3cd4424b7b8ae700dc3be5da210a199
font_02_sfnt_off00019e35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19E35 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1