Malicious PDF — malware analysis report

Static analysis result for SHA-256 718c438e88f01eb8…

MALICIOUS

PDF

87.1 KB Created: 2021-09-01 21:27:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: ebab158e46c6d2092f747dc9a7b86315 SHA-1: 96f83c0f08c264f743b4bcad54de1802eab91bef SHA-256: 718c438e88f01eb8afcb73fa63dc0bc1f04b1967f11cc6cd23c5b3639a170aef
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many pointing to compromised WordPress sites, suggesting it functions as a link farm for phishing or malware distribution. ClamAV detected this file as Pdf.Phishing.Trojan, and ML classifiers also flagged it as malicious. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://infrive.ru/uplcv?utm_term=meaning+of+studious+in+english PDF link annotation
    • http://stylist.in.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160729c1d74255---dudefumukogabe.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160856fd8db89c---81256871842.pdfIn PDF document text
    • https://www.skyline-recruiting.com/wp-content/plugins/super-forms/uploads/php/files/eab3cd12b1b1a7c4d8b8e557e90d7648/30350964458.pdfIn PDF document text
    • http://sampsonancestry.com/clients/d/d9/d9bd9208c4e45de01aa31840e3a8c66b/File/texuvevujituk.pdfIn PDF document text
    • https://zold-kommando.hu/files/47520318143.pdfIn PDF document text
    • http://www.naturapreserved.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074b1a76d690---53708681812.pdfIn PDF document text
    • https://okazionche.com/files/35045078656.pdfIn PDF document text
    • http://ergakiland.ru/files/files/waviderebeg.pdfIn PDF document text
    • http://benevolo.it/userfiles/files/85323768259.pdfIn PDF document text
    • http://www.gunyagder.org.tr/wp-content/plugins/super-forms/uploads/php/files/pf6pjehms6bl7ihgn6j7j3umd3/kosenuzu.pdfIn PDF document text
    • http://moonlightmontessori.com/upload/files/60827680888.pdfIn PDF document text
    • http://russia-ex.com/images/blog//file/83739128703.pdfIn PDF document text
    • http://stihoplet.by/upload/editor/files/jafivo.pdfIn PDF document text
    • https://aucordechasse.fr/vosImages/mopevubipatazezuburafuno.pdfIn PDF document text
    • http://abwlanham.com/uploads/files/83368455653.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/81758244256.pdfIn PDF document text
    • http://mosjob.ru/images/file/48064819920.pdfIn PDF document text
    • https://hotelmitrutarija.com/uploaded/files/juvediratexuze.pdfIn PDF document text
    • http://www.taylormadetc.com/siteadmin/ckfinder/userfiles/files/15715159778.pdfIn PDF document text
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1609bf523ce627---87267711030.pdfIn PDF document text
    • https://pharmnet.cz/ckfiles/files/files/54723955400.pdfIn PDF document text
    • https://www.superioreagle.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c791fbb9367---55057673639.pdfIn PDF document text
    • http://cimkezes.hu/uploads/ckfinder/userfiles/files/fasonig.pdfIn PDF document text
    • https://loctra.net/userfiles/file/96399255265.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_off0000df19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF19 24388 bytes
SHA-256: 86c4b63bc5ef4e3cf3f84499891f44f1a4f2c59d7a12e78b30e53224df67ea32
font_01_sfnt_off00011e28.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E28 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001363f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1363F 10628 bytes
SHA-256: b859a7359e02d79832fc0b93d4d133674ac3facb87dd0aa3c46ace02588bf9fe

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