Malicious PDF — malware analysis report

Static analysis result for SHA-256 b59885fb5733ce46…

MALICIOUS

PDF

119.9 KB Created: 2021-07-16 06:00:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: d9b9e0325ecd7bc4b073980beb9ab1ba SHA-1: 469261db2fb73cf1497f920e2ebbb8d02a755d03 SHA-256: b59885fb5733ce46fb2784c4465415ae2d5b4ce9b65be52fc12a0026b95d7433
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple compromised WordPress upload storage locations and other disposable hosting sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f1ab9d7b78---81807977769.pdf In PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/mpffil4g9qse7620hupulftco3/41518303517.pdfIn PDF document text
    • http://seoulsquare.com/userfiles/file/zazof.pdfIn PDF document text
    • http://ahcxdq.com/uploads/file/030601473153.pdfIn PDF document text
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160ac68dfef6a1---64527040386.pdfIn PDF document text
    • https://tenekedjieva.com/uploads/file/lefivetogudov.pdfIn PDF document text
    • https://www.harasportcenter.com/wp-content/plugins/super-forms/uploads/php/files/4d5b6fbc9fut61ndnq9t8fk6df/76845078778.pdfIn PDF document text
    • http://bhttourist.com/upload/fckimagesfile/947701914.pdfIn PDF document text
    • http://wksystems.net/HotelEstimator/userfiles/file/lupekux.pdfIn PDF document text
    • http://budohurtsa.pl/userfiles/file/duzomew.pdfIn PDF document text
    • https://travelworld.ro/userfiles/file/jijobukaguxelazubiz.pdfIn PDF document text
    • https://www.couleurs-et-jardin.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16072f9f62aaa6---misijasotelube.pdfIn PDF document text
    • https://www.kiteschule-eckernfoerde.de/wp-content/plugins/formcraft/file-upload/server/content/files/160e22bec9a138---2228077192.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160bcf0a37b95b---7220481597.pdfIn PDF document text
    • https://webmodeli.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c5fa0f0618---xubutebotunires.pdfIn PDF document text
    • http://stoewebdesign.no/userfiles/file/49472530345.pdfIn PDF document text
    • https://akarchlight.com/wp-content/plugins/super-forms/uploads/php/files/ba371fcf2e724b0cb65a837b9e30b640/gukenajafirewaxumigutiw.pdfIn PDF document text
    • http://gps-tw.com/CKEdit/upload/files/58477790171.pdfIn PDF document text
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160934f2a59d14---sejivokipepo.pdfIn PDF document text
    • https://www.citysecurity.org.uk/wp-content/plugins/super-forms/uploads/php/files/4224eppe1p204ro4gu91ptagh3/zusupenemivafarotel.pdfIn PDF document text
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/vdq32rdp60hl3tbmdjlkn0f6q6/rovivixadunefesodabis.pdfIn PDF document text
    • http://smartwealthhk.com/userfiles/53204416144.pdfIn PDF document text
    • http://lexen.ca/userfiles/files/jomakaxuzo.pdfIn PDF document text
    • http://dom-nenilovo.ru/wp-content/plugins/super-forms/uploads/php/files/b4d65874ea186b1e22f57fdbe12784ee/lebupododelivipituvawezex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=tropical+rainfall+measuring+missionPDF 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_off000170ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x170EA 10788 bytes
SHA-256: 5c5492537813c6eb2152f9b2ee893939392a99ca01eacd38a8391b11b36b0895
font_01_sfnt_off000189b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x189B4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001a1c6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1A1C6 18220 bytes
SHA-256: c295fd97ee4a443147e4880ce3d5911eaa4f45951092baabe72647d3108a3a9e