Malicious PDF — malware analysis report

Static analysis result for SHA-256 773b9b637f3d5132…

MALICIOUS

PDF

83.6 KB Created: 2021-08-16 18:03:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: a5fbf313805cd28f82d1ce2dcbedfc50 SHA-1: 86dd1dd0a04b47e24d08f3f81529cc45f78bec7f SHA-256: 773b9b637f3d513264027088a2e45183d56cbb8d51914cf40e9894295fdf11df
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links, many pointing to compromised WordPress upload directories or disposable hosting, suggesting a link farm used for SEO manipulation or to distribute malicious content. The document body is heavily obfuscated and unreadable, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

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://medvor.ru/uplcv?utm_term=what+is+the+key+difference+between+simple+interest+and+compound+interest PDF link annotation
    • http://allnatureint.com/userfiles/file/wosidisilixudodagub.pdfIn PDF document text
    • https://dewalt-naradi.cz/media/upload/editor/file/82175689903.pdfIn PDF document text
    • http://driver-jazda.pl/upload/file/faleragebikera.pdfIn PDF document text
    • https://kvgrup.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160b2ab3091260---10394023995.pdfIn PDF document text
    • http://ctyrkolky-gamax.cz/data/dokumenty/kubilewi.pdfIn PDF document text
    • http://bjerkelunden.org/content/files/userfiles/file///nazosugewitumarusafuvefop.pdfIn PDF document text
    • https://stollerco.com/testingsites/advantage_aviation/assets/media/file/zumimemo.pdfIn PDF document text
    • https://dukeofmarshall.com/ckfinder/userfiles/files/52223716047.pdfIn PDF document text
    • http://anandamsanyal.com/userfiles/file/gidapudeweferugezo.pdfIn PDF document text
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/160881f15ae847---gujafefe.pdfIn PDF document text
    • http://www.virtualaid.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1610e39ca2719a---bepojiwepetok.pdfIn PDF document text
    • http://global-poseg.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2bcb6510c9---notibarusimimixi.pdfIn PDF document text
    • https://elektrona.cz/files/file/3014186686.pdfIn PDF document text
    • http://finsura-lifedirect.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607b74589e4b7---xakuzaluzoguzovidupebipem.pdfIn PDF document text
    • http://xn--d1achljw0b.xn--p1ai/content/upload/vasifokumusazusuto.pdfIn PDF document text
    • http://firanywiktoria.pl/uploads/editor/file/93137319133.pdfIn PDF document text
    • http://launensia.cz/ckfinder/userfiles/files/tevaxetamedawama.pdfIn PDF document text
    • http://pallenberg-busreisen.de/uploads/files/83495692616.pdfIn PDF document text
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cb43e80d26e---kopamokivu.pdfIn PDF document text
    • http://huron81reunion.com/clients/f/fe/feec28e48c841af8be4ad6373737a022/File/pisiw.pdfIn PDF document text
    • http://cameronhaddock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d92944ecff5---wanukaxo.pdfIn PDF document text
    • https://iringmalaysia.com/ckfinder/userfiles/files/54444874654.pdfIn PDF document text
    • http://gapoom.com/upload/fckeditor/file/27970995560.pdfIn PDF document text
    • https://tcufroghouses.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072e5781c43c---xovukirovetadikupa.pdfIn PDF document text
    • https://www.cr-sdc.org/wp-content/plugins/super-forms/uploads/php/files/70af7a881dee8389d0de12be181619ed/95350069886.pdfIn PDF document text
    • http://www.benyowsky.com/resources/files/rididigexivipuvuvugolo.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160c98f32c6494---bofukazorinumepekezatiz.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16079998ec205b---gutomokijokedeziju.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_off0000e223.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE223 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fa3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA3A 11408 bytes
SHA-256: b8742c338edf3ce2029dbe267d887b6534fac989e109acc4e74cead4ed95a7e4
font_02_sfnt_off000114d2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114D2 16744 bytes
SHA-256: 9fef137f4523ef7725e403f97408dd0a080a7231048cd8531ecaffadaa4b5ad7

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