Malicious PDF — malware analysis report

Static analysis result for SHA-256 af3a021f1ee2fae3…

MALICIOUS

PDF

68.9 KB Created: 2021-09-01 14:51:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: fcdaa62447ec11731fcbe808022988d3 SHA-1: 8753d18541a8e4ee6d3fada1d1fa3c34156ce21c SHA-256: af3a021f1ee2fae3c196d48d3a283038e68e7e03b6e1b27df81a7117a8bb06b7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous links, many pointing to compromised CMS uploads and disposable hosting, indicating a link farm designed for phishing or malware distribution. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or delivering a secondary payload. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond what the heuristics reveal.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 http://mmckno2010.zkosuchdol.info/files/61910747044.pdf In PDF document text
    • http://itaindustrial.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ae351027d82---68729722990.pdfIn PDF document text
    • http://countrysquirefoods.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609565aa234f7---10988551378.pdfIn PDF document text
    • https://www.wsbe17hongkong.hk/_bin/ckfinder/userfiles/files/85649366909.pdfIn PDF document text
    • http://verkoop-je-wagen.be/wp-content/plugins/formcraft/file-upload/server/content/files/16095e7fe6158b---lewevulokuxoloxigemirokab.pdfIn PDF document text
    • https://www.kiteschule-eckernfoerde.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a27c1e1b0f7---kipijixenu.pdfIn PDF document text
    • http://omgmediatank.com/userfiles/files/kupal.pdfIn PDF document text
    • https://qualitymattressfactory.com/admin/userfiles/file/87784075938.pdfIn PDF document text
    • https://alrukn.co/userfiles/files/96429474424.pdfIn PDF document text
    • http://club-integra.ru/userfiles/file/vaguwire.pdfIn PDF document text
    • http://bsbcarpet.com/userfiles/file/goramalunosogik.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/e02e22110614e71d90aacd37961b4d11/natifaw.pdfIn PDF document text
    • https://inijariku.com/ckfinder/userfiles/files/61683957371.pdfIn PDF document text
    • https://babetravelling.com/ckfinder/userfiles2/files/kokufurobewup.pdfIn PDF document text
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/76b017b78f980e08978333c82e1d7461/xogunikajupotonos.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608d75892f69c---xefizi.pdfIn PDF document text
    • http://chatsworth72.com/clients/5/53/532ec3c8dc0e95779814939736d4df6d/File/funadejinixiwawago.pdfIn PDF document text
    • http://dungcubepgiangtrinh.com/webroot/img/files/26293107322.pdfIn PDF document text
    • http://markone-tools.com/upload/files/74065704829.pdfIn PDF document text
    • https://masukpt2.com/contents//files/88739233110.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/160c1590e9a481---53612983116.pdfIn PDF document text
    • http://arci-mp.fr/admin/File/serapivijokuzi.pdfIn PDF document text
    • http://greece-ex.com/images/blog/file/58735865027.pdfIn PDF document text
    • http://yves-segers.be/userfiles/files/zeritojojulisozogizu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=d%26d+5e+staff+of+frostPDF 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_off0000b774.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB774 14444 bytes
SHA-256: 26c612888d3d9c7bea2f81ef5fb153d0d1c3f4bb9bdbda5ba9f2661d85ab89a7
font_01_sfnt_off0000db94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB94 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f3aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3AA 9076 bytes
SHA-256: f695977626623e59fedb2fbedebd468d0acf89ff6f6ceafeb3cee4351ddee6c8