Malicious PDF — malware analysis report

Static analysis result for SHA-256 37fd8431188d88f6…

MALICIOUS

PDF

87.9 KB Created: 2021-06-29 12:24:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: fe6ceb2060df96b60437f492c7a74cf1 SHA-1: dd802931f1ff25a155c2a78c10d833cc3f059f36 SHA-256: 37fd8431188d88f67decfb170aca20686b3943a802fc7e763af22e298870fd5d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised WordPress sites, suggesting a phishing or malware distribution campaign. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this, as these are common tactics for hosting malicious content or redirecting users. No scripts were extracted, but the PDF structure itself is used to facilitate the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9835

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://triosms.com/userfiles/file/wodim.pdf In PDF document text
    • https://www.msolartop.cz/wp-content/plugins/formcraft/file-upload/server/content/files/1609e5fd04874a---romuvopikitux.pdfIn PDF document text
    • https://playgametoday.ru/wp-content/plugins/super-forms/uploads/php/files/6deb98cbef3c45d0f7b202b929a6c438/3314945512.pdfIn PDF document text
    • https://cvsc.co/userfiles/file/fozajodepujagamud.pdfIn PDF document text
    • https://www.wflorlando.com/wp-content/plugins/super-forms/uploads/php/files/4bf9c0090dd6bbf29dae82bde5165386/waxogorarikubogexarobisaj.pdfIn PDF document text
    • https://calldidocta.com/wp-content/plugins/super-forms/uploads/php/files/295fc72efc3b854f50402eed03e9b885/zubegekejovexolebes.pdfIn PDF document text
    • http://bellezaeimagen.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1609b91e768577---wijuvamujum.pdfIn PDF document text
    • http://showplus.ae/userfiles/files/kafosegosatexixesevijexa.pdfIn PDF document text
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/1c058ed290b37bb81d3bdd4cde748db0/91922376946.pdfIn PDF document text
    • http://gorisum.net/fckeditor/upload_file/file/kozekulikep.pdfIn PDF document text
    • https://www.formwork.co.uk/wp-content/plugins/super-forms/uploads/php/files/nj6c276698n03smm9g2mldl5lq/texafamuwiminow.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8c0565917a---14932783101.pdfIn PDF document text
    • http://eventcompany.org/clients/e/e3/e30ef11cf4efe639fe6592aa37b9cb94/File/pexulanepukowomugogemu.pdfIn PDF document text
    • https://regeneracion-capilar.com/wp-content/plugins/super-forms/uploads/php/files/0e6dbad68e31b2e45026a681e893fb6a/77941690170.pdfIn PDF document text
    • https://ienter.bg/files/gumibagisu.pdfIn PDF document text
    • https://pharma-tools.eu/galeria/file/zirozet.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1607c7fc55b056---61493887342.pdfIn PDF document text
    • https://nothingbutsafetyglasses.com/userfiles/file/pepizisefudenotuwugoturo.pdfIn PDF document text
    • https://namdolove.com/FileData/ckfinder/files/20210609_A1A3E675781E3FD0.pdfIn PDF document text
    • http://guowangcable.com/d/files/pamegevanawine.pdfIn PDF document text
    • http://ohsclassof73.com/clients/9/9a/9a21b0b253f7c4eafe662346d237c286/File/neloposufikiriranixijumup.pdfIn PDF document text
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/160b846ca9cc3e---fuwafudujovozotodojoruto.pdfIn PDF document text
    • https://carpanea.it/wp-content/plugins/super-forms/uploads/php/files/545be22304167c632f6cd406b49e728c/xulevuwanos.pdfIn PDF document text
    • https://mindspacepsytherapy.com/upload/ckfinder_temp/files/20210528010655.pdfIn PDF document text
    • http://msslink.ru/userfiles/files/rujulorixeg.pdfIn PDF document text
    • https://rosemonttherapy.health/wp-content/plugins/super-forms/uploads/php/files/tpadpuaa89r2h3ctsggethred5/50991079703.pdfIn PDF document text
    • https://k9-warrior.com/wp-content/plugins/super-forms/uploads/php/files/1ocmopqqtqjj1pjj0gvv9es8ld/jegitagene.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=textbook+pdfs+downloadPDF 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_off0000f4bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4BC 17268 bytes
SHA-256: fd8d20e60ce8aeb84d2c788a91d3d51fbb42dd16f78fc382d0d0a40132ff0fd4
font_01_sfnt_off000121b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121B2 10680 bytes
SHA-256: 0f970e005e75cb5133bbd6215410f0830621044f10cc603c0761631563eb5fe2
font_02_sfnt_off00013a3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A3F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1