Malicious PDF — malware analysis report

Static analysis result for SHA-256 90811ef2903e434e…

MALICIOUS

PDF

80.0 KB Created: 2021-09-06 06:49:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 36b734d3e8a5e1a3415ea65670115049 SHA-1: 449be021e43d33b898f9a111f1eebc9bee5f9c9a SHA-256: 90811ef2903e434e844b01471642d8337d6a29c7f9af61d482dad56eae8f0323
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly support its malicious nature. The document body is heavily obfuscated and appears to be metadata from the wkhtmltopdf tool, providing no direct user-facing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://cartopack.com/Images/file/nimuku.pdf In PDF document text
    • https://ozmutludokum.com/userfiles/file/96817833085.pdfIn PDF document text
    • https://cdmsig1.com/ckfinder/userfiles/files/sedukigezakuzoveter.pdfIn PDF document text
    • http://scoutpate.com/userfiles/file/2678032075.pdfIn PDF document text
    • http://shopgraeagle.com/ckeditor/uploads/files/kuxevadix.pdfIn PDF document text
    • http://sladkiy-ostrov.ru/userfiles/files/803999178.pdfIn PDF document text
    • https://aljazeerahpetroleum.ae/userfiles/files/61507535539.pdfIn PDF document text
    • http://debandhelder.nl/ckfinder/userfiles/files/rigaleze.pdfIn PDF document text
    • http://abogadosaguilar.com/ckfinder/userfiles/files/xoweminururanarineviniwip.pdfIn PDF document text
    • https://functionalmovement.gr/wp-content/plugins/super-forms/uploads/php/files/d7826b30f07e2918fe622642f397d80e/66560706060.pdfIn PDF document text
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/2a7b0606579070bda4e8174039fa872f/vafalawemugi.pdfIn PDF document text
    • https://digireg.se/upload/wuxaza.pdfIn PDF document text
    • https://homeaestheticsllc.com/wp-content/plugins/super-forms/uploads/php/files/aecdaff1f87b0ffe772db38ab99542fa/galerosamunexujulatotej.pdfIn PDF document text
    • http://frederickfollows.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160a0ce406ebc9---bodakixoganedotowoziwen.pdfIn PDF document text
    • http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/160967cfd16764---70402371591.pdfIn PDF document text
    • https://www.lokalesichtbarkeit.de/wp-content/plugins/super-forms/uploads/php/files/i3i8vvs4uitcc4j84ue3nsa0rp/moxifuboduxu.pdfIn PDF document text
    • https://yournew.site/wp-content/plugins/super-forms/uploads/php/files/d4t7145q9v83pk6pk1a31545he/46210231644.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608cddfb0c34c---fexofigu.pdfIn PDF document text
    • https://www.mercato.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160baf4561b03b---85014080094.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160bdd5b29dc54---60050333892.pdfIn PDF document text
    • http://biemmecommerciale.eu/userfiles/files/kuriwodanupafijijumemulij.pdfIn PDF document text
    • https://kipass.fr/userfiles/file/xizazupogoxit.pdfIn PDF document text
    • http://www.greddy.com/admin/common/ckfinder/userfiles/File/guxabovajubofomesovosujej.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=beginning+solfege+worksheet+%2311+answer+keyPDF 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_off0000d25c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD25C 10564 bytes
SHA-256: b8a82280658cae8feedafdfa02610ece3f935b179a87d03cebba4fc35e5123b9
font_01_sfnt_off0000ea72.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA72 18452 bytes
SHA-256: 140e47c0a862c43df160ffa2f4277dad5fcabf62fed3df8fffd8a7cdf942d17d
font_02_sfnt_off00011a7c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A7C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1