Malicious PDF — malware analysis report

Static analysis result for SHA-256 4524d03aeeb56e55…

MALICIOUS

PDF

88.0 KB Created: 2021-09-03 16:00:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 1fd0f5a930c86fadb1f247a2e594e90d SHA-1: 2889fcc51211eab72d0899518de0ce3e345aad7d SHA-256: 4524d03aeeb56e552744839d1cd49baf274f1d5e8979580ae169fb8e0faf15e7
156 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs, many of which point to compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or SEO spam. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a vehicle for the embedded 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://synerhu.ru/uplcv?utm_term=manual+pedal+digitech+rp90+espa%C3%B1ol PDF link annotation
    • http://topopentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16117a64943d4e---zojedi.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/vutezowe.pdfIn PDF document text
    • http://naasschoolofmotoring.com/fckeditor/userfiles/file/nukatofebopusipuj.pdfIn PDF document text
    • https://artbynela.com/uploads/file/vigupemiromekelodotele.pdfIn PDF document text
    • http://crisismobile.com/ckfinder/userfiles/files/40410186268.pdfIn PDF document text
    • http://rintoyo.com/userfiles/file/91518374154.pdfIn PDF document text
    • http://gsoam.ge/wp-content/plugins/formcraft/file-upload/server/content/files/16076df2804ac9---gevimavob.pdfIn PDF document text
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160a2782eb2737---sasevugiw.pdfIn PDF document text
    • http://iberia-ex.com/images/blog//file/58905061909.pdfIn PDF document text
    • https://www.ayersworthglen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fb7ddbbc4bb---82058314999.pdfIn PDF document text
    • https://giverny-bkk.com/upload/files/38459117624.pdfIn PDF document text
    • http://vinag7furniture.com/app/webroot/files/editor_upload/files/30512112244.pdfIn PDF document text
    • http://akicgiyim.com/userfiles/file/94632011599.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16081404ad121a---77453113911.pdfIn PDF document text
    • https://nbtele.com/en/cache/fck_files/file/taneva.pdfIn PDF document text
    • http://liveranigioielli.it/userfiles/files/tebixekujaworixumejadugo.pdfIn PDF document text
    • https://daluxerealty.com/wp-content/plugins/super-forms/uploads/php/files/gi31ogjidp6klkta1n4q7di0l3/25499442684.pdfIn PDF document text
    • https://oteaexpert.fr/cite_imgs/file/mukidobovak.pdfIn PDF document text
    • http://www.adarshvidhyasankul.org/userfilesfile/kivub.pdfIn PDF document text
    • http://abwmarlboropike.com/uploads/files/82349866956.pdfIn PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b00b9b11ccd---89705062032.pdfIn PDF document text
    • http://morard-mcf.fr/data/Files/60914918718.pdfIn PDF document text
    • http://alkanboya.com/files/file///93505525381.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_off0000eed2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEED2 11380 bytes
SHA-256: c51b4cc612e1a712334c570d66919fe9846433cf245f0bd8fd385a61fc4e9289
font_01_sfnt_off0001090e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1090E 18148 bytes
SHA-256: 119a2e2c5770a1bb941ccc0331d81fb11b432be2451c8a39edee9f795d7c500f
font_02_sfnt_off000137e6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x137E6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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