Malicious PDF — malware analysis report

Static analysis result for SHA-256 550aa24e9cbecb23…

MALICIOUS

PDF

81.2 KB Created: 2021-09-03 06:05:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 41a652b352841916b81b680ef5884166 SHA-1: 5733e4cdaab823da2e91739a10dde93aaa3a0128 SHA-256: 550aa24e9cbecb237cd689e8d28fcaa7d4bb9d7d7aa1df119d613e6cb62cfedc
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised WordPress upload directories or disposable hosting, suggesting a link farm designed to redirect users. The PDF structure and embedded URLs are consistent with phishing or malware distribution campaigns, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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://drafthe.ru/uplcv?utm_term=english+tenses+formulas+pdf PDF link annotation
    • http://haenuri.net/ckupload/files/43005396223.pdfIn PDF document text
    • http://local-minicab.com/survey/userfiles/files/zoladiduguxuzopij.pdfIn PDF document text
    • http://gtshotel.it/images/file/2845033846.pdfIn PDF document text
    • https://vannordenvastgoed.nl/userfiles/file/58088110860.pdfIn PDF document text
    • https://edukiya.com/wp-content/plugins/super-forms/uploads/php/files/786f9e07c7a35b90b8676e0e18932ade/25792699895.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/7a86a36bb569487a4788ee7c03ce8048/98411478651.pdfIn PDF document text
    • http://pelesiuvalymas.lt/i/File/nelateterekofu.pdfIn PDF document text
    • http://fsnmmaterials.com/UPFILE/userfiles/files/tidogurisavowotolu.pdfIn PDF document text
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/5b8c83162dd2287ccc0c8e6940757130/36459071916.pdfIn PDF document text
    • http://itemclinicchina.com/ckupload/files/95392546998.pdfIn PDF document text
    • http://jrpst.pl/userfiles/file/5183237569.pdfIn PDF document text
    • https://path.mn/userfiles/files/sujonezoj.pdfIn PDF document text
    • http://nordicaluminium.ru/userfiles/file/takekonofejomod.pdfIn PDF document text
    • https://cengilli.com/icerik_images/file/duruxuxajumipal.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/5jh7n6tqp7tdhns3mj0ndf4t52/79545796015.pdfIn PDF document text
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160a571fd7964d---difemibofaz.pdfIn PDF document text
    • http://nickelsgrafikdesign.de/ckfinder/userfiles/files/37469099438.pdfIn PDF document text
    • http://srsheicha.com/uploadfile/file/34746311806.pdfIn PDF document text
    • https://www.rowtheerne.com/wp-content/plugins/super-forms/uploads/php/files/19e818f3c0f6f8a77628de1fbf5b57fb/gexezefud.pdfIn PDF document text
    • http://vtaky.sk/media/file/vitifisupubu.pdfIn PDF document text
    • http://caigeshi.com/uploadfile/file/2021082121532173499.pdfIn PDF document text
    • 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_off0000d8d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8D6 11028 bytes
SHA-256: 18518fb0434506d1c78943d016504f4bffba2ac42b456524d8b1cc1f1702ffd5
font_01_sfnt_off0000f20c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF20C 17508 bytes
SHA-256: 38a630ae0a8271b0196ded820da09ab23903b1091bcaceecb71b70206c23f5ec
font_02_sfnt_off00011f93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F93 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1