Malicious PDF — malware analysis report

Static analysis result for SHA-256 b37e71d3b89823f4…

MALICIOUS

PDF

85.0 KB Created: 2021-09-16 09:17:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: c4a617b7bdb851add3c4099a44bcbec8 SHA-1: 30a1ed8b8082910a990c673ff20c8f41531e7500 SHA-256: b37e71d3b89823f4648894b4121afce9551b3cc893c492c5e2c5be2e2eb6b4a4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of external links, many of which point to compromised WordPress upload directories or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to lead users to phishing or malware distribution sites. The presence of numerous links suggests a link farm attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://acrgruppe.de/userfiles/file/tumusasu.pdf In PDF document text
    • http://aktifbant.com/resimler/files/63040638039.pdfIn PDF document text
    • http://aa-nusd.jp/nuwesesib.pdfIn PDF document text
    • http://ambulatorioveterinariocamali.com/userfiles/files/24773760007.pdfIn PDF document text
    • http://milwaukee.center/userfiles/file/74132700305.pdfIn PDF document text
    • http://thestarbusan.net/FileData/ckfinder/files/20210916_B6A5B52324121686.pdfIn PDF document text
    • http://mayingiabao.com/upload/files/lofekajun.pdfIn PDF document text
    • http://rehahomecare.com/upload/editor/files/wipujalopifigalo.pdfIn PDF document text
    • http://thietbiotoviet.com/Images_upload/files/vovepagazatu.pdfIn PDF document text
    • http://igs.compcierge-asia.com/ckfinder/userfiles/files/zefegiwajalavokebove.pdfIn PDF document text
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161391b0844e76---30916528716.pdfIn PDF document text
    • http://hycxchina.com/filespath/files/20210904142731.pdfIn PDF document text
    • http://grimastone.ru/files/85059872143.pdfIn PDF document text
    • http://master-stroi76.ru/userfiles/file/67693228421.pdfIn PDF document text
    • http://ekbdrive.ru/ckfinder/userfiles/files/woravenixonowiruvujakulix.pdfIn PDF document text
    • http://dunakeszi.varosom.hu/userfiles/files/sixovuvakamu.pdfIn PDF document text
    • http://leinerpakgelatine.com/survey/userfiles/files/jagolitawojopagujepuro.pdfIn PDF document text
    • https://himalayanwanderer.com/himalayan/userfiles/files/80222719097.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1613f99629ac1b---21087723369.pdfIn PDF document text
    • https://levin-dent.ru/wp-content/plugins/super-forms/uploads/php/files/d67f4ad0c16cb4d1e81b4adb91895a59/59562590965.pdfIn PDF document text
    • http://fotografiafrancescosomma.com/userfiles/files/giwapojigudikeliloj.pdfIn PDF document text
    • https://www.smartfutureexpo.com/ckfinder/userfiles/files/28626771856.pdfIn PDF document text
    • http://vxclouds.com/userfiles/file/78095406540.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=pokemon+mystery+dungeon+dx+yuzuPDF 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_off0000db30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB30 10760 bytes
SHA-256: b816fef2ef82fa2478dfa84547e7d59d47868bac411b9463b40c8f6c17bb8578
font_01_sfnt_off0000f3d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3D4 22624 bytes
SHA-256: 09624dda73559875c11df609985d8cd295e54e6fac90c8a01c2d4b6292205d39
font_02_sfnt_off00012e79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E79 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1