Malicious PDF — malware analysis report

Static analysis result for SHA-256 519db3c266798c50…

MALICIOUS

PDF

73.7 KB Created: 2021-07-18 19:30:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 62c2242de2cb3f49866f608cda08f21f SHA-1: 484809bd7285ecdd0733921c58afd9f93acb4200 SHA-256: 519db3c266798c506320515f5baff1ea530db7a3727b35362516f99e3add8e7e
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The sample is a PDF containing embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities. The heuristics indicate that the PDF acts as a link farm, directing users to multiple compromised websites. This behavior, combined with the ML classifier and ClamAV detection, strongly suggests a malicious intent, likely for phishing or to serve a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://maytinhtuyenquang.com/home/maytinhtuy/domains/maytinhtuyenquang.com/public_html/images/file/44176973173.pdf In PDF document text
    • http://birons.net/wp-content/plugins/super-forms/uploads/php/files/ced6ae44914229843853630d24079db7/36862899775.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160989736b87ed---69053796202.pdfIn PDF document text
    • https://hcs1000.org/wp-content/plugins/super-forms/uploads/php/files/0928ec7f0ec8a0158be115f39c2d216f/10555366210.pdfIn PDF document text
    • https://www.limratechnologies.net/wp-content/plugins/formcraft/file-upload/server/content/files/16076b35d89089---22759077715.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/d8fbfe0f4519385f9db6d3d8ebf19a7c/21485369981.pdfIn PDF document text
    • https://ferdavagnar.is/images/fck/file/midefosekusewu.pdfIn PDF document text
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074d922c55f1---65142597289.pdfIn PDF document text
    • http://illinoislivestock.org/userfiles/file/fisanejixuleligov.pdfIn PDF document text
    • https://functionalmovement.gr/wp-content/plugins/super-forms/uploads/php/files/0c0e13668a23a4744c7fdd4812a9d852/memub.pdfIn PDF document text
    • https://www.cr-sdc.org/wp-content/plugins/super-forms/uploads/php/files/83a29226d01fc4c264df3ddd4bfaf931/73488042239.pdfIn PDF document text
    • http://to-kajihan.net/js/upload/files/penezujamezubevifuduzox.pdfIn PDF document text
    • https://higher-reason.com/wp-content/plugins/super-forms/uploads/php/files/5jc6t86cqmd6c9k3otv42jqec0/485259700.pdfIn PDF document text
    • http://www.benyowsky.com/resources/files/9955188468.pdfIn PDF document text
    • https://andrejc.si/files/file/62581274130.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-5-29/20210529050856296819.pdfIn PDF document text
    • http://chickendaylacrescenta.com/uploads/files/13199546769.pdfIn PDF document text
    • https://frasertechno.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609494170fda8---juwugewejutowisafaj.pdfIn PDF document text
    • https://www.herewardcarpets.co.uk/wp-content/plugins/super-forms/uploads/php/files/ip3h5lai2mmnu5j3n3d3lk5sju/94861312871.pdfIn PDF document text
    • https://rhythmcprandfirstaid.com/wp-content/plugins/super-forms/uploads/php/files/c5d986d6d5acfa6d926a274ac676c821/riwewubuwunoxoxiruj.pdfIn PDF document text
    • http://regimhotelierbucuresti.com/images/userfiles/97107263635.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=ncert+science+class+9+chapter+7+solutionsPDF 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_off0000bf8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF8E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d7a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7A0 16044 bytes
SHA-256: 862e27f1acd55e605e4b6735734c63458c176ef2c2863702ed5588250ac623d6
font_02_sfnt_off000100d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100D6 10768 bytes
SHA-256: 4b9b9900fcdfd3fb066614e415fd0960ff8e434e866231db5e726d4d9b1654f7