Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bc4ad23e35f82f…

MALICIOUS

PDF

81.4 KB Created: 2021-09-01 07:26:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: e1fd3c804925fee5381e8d3ff9f64629 SHA-1: a806c22b763ba5ba8717f9af2b07ca253d1753ec SHA-256: 81bc4ad23e35f82fc381a586c6f0e02761606a0203e5ba0e804e5440d72c0da5
156 Risk Score

Malware Insights

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

The PDF file contains a link farm directing to numerous URLs, many hosted on compromised CMS platforms. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests an attempt to leverage search engine optimization for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://allcreaturesinc.com/files/files/nugemasojo.pdf In PDF document text
    • https://braindevelopmentmaps.org/userfiles/files/96535651292.pdfIn PDF document text
    • http://fuga-hotel.com/CKEdit/upload/files/57196304266.pdfIn PDF document text
    • http://cucthongke.vn/userfiles/file///vomagoli.pdfIn PDF document text
    • http://seoulmenu.com/uploads/files/pibuwekexupokup.pdfIn PDF document text
    • https://cissud.com/uploads/ck_editor/files/44708955931.pdfIn PDF document text
    • https://ketgate.eu/wp-content/plugins/super-forms/uploads/php/files/d76fda923ad58582a3f5bbb9bd59588a/88125077805.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1606c750d472de---wamanavafanimugupozexam.pdfIn PDF document text
    • http://matsonconstruction.net/userfiles/file/94862795048.pdfIn PDF document text
    • https://karolinanowak.com/userfiles/file/begakubuzerad.pdfIn PDF document text
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b2f260950a0---tapekaposu.pdfIn PDF document text
    • https://vsetinrally.cz/userfiles/file/musifupopuzipomesux.pdfIn PDF document text
    • http://rencontres-icare.org/userfiles/file/tozetisiwilebuberemigasi.pdfIn PDF document text
    • http://fritz-fahrlaender.ch/download/vudibosixozi.pdfIn PDF document text
    • https://www.isnb.co.uk/wp-content/plugins/super-forms/uploads/php/files/35876172d0e51e9f9ecfd283550eb051/muguwagoraloxigu.pdfIn PDF document text
    • http://inspiredindianfoundation.org/uploads/90995792916.pdfIn PDF document text
    • https://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/fnt7325eb3g001tks5u9nop1ef/25058865873.pdfIn PDF document text
    • http://mamaskitchenorder.com/uploads/files/48591177023.pdfIn PDF document text
    • http://studiodebiaggi.eu/userfiles/files/87256314230.pdfIn PDF document text
    • https://pablohernandes.com/wp-content/plugins/super-forms/uploads/php/files/54c0e74d783ed00d8bcce236808216d7/87177636479.pdfIn PDF document text
    • https://worldkelo.com/wp-content/plugins/super-forms/uploads/php/files/a622f88a2a64eacf874d2bbd4e21703d/rugatojidamuw.pdfIn PDF document text
    • https://raiporjai.com/piceditor/file/revovuwipodeg.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/8tonnssugu5hfct63ic6n7kokq/63179078829.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b28bdba344a---lupumutalubeve.pdfIn PDF document text
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/2fe3fa59652743227515fdaaadd87206/gatimaduwa.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=professional+office+cleaning+services+near+mePDF 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_off0000d9de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9DE 17768 bytes
SHA-256: 16ca7838fa69a9291e0393e3c8ca143400151728177eefed6e431e60cbd393db
font_01_sfnt_off0001071a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1071A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011f31.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F31 10648 bytes
SHA-256: d4a8075cfc3ee617633a5cf7032f6c39c7eb299a525cca295cf4af99f555c7ce