Malicious PDF — malware analysis report

Static analysis result for SHA-256 635a0c957f1ceab2…

MALICIOUS

PDF

76.0 KB Created: 2021-09-25 21:15:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: d935c63d06e373fb71a4c9cff940072a SHA-1: 423eaf181212d8fc8b073a05a2d3d3bee433c97a SHA-256: 635a0c957f1ceab26a1048efe02db720f55d24d799b9f3525f969de189d72916
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains numerous links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm for SEO poisoning or phishing. While no scripts were explicitly extracted, the PDF structure and link farm behavior indicate a malicious intent to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 http://liceoadultos.juniorcollege.cl/userfiles/files/xijafibofegejumuz.pdf In PDF document text
    • https://asigurareingermania.ro/wp-content/plugins/super-forms/uploads/php/files/qkl4hkaht9n45k9i6lq00h68r0/86934299941.pdfIn PDF document text
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1614b7f69b6a2d---jokibiwuvekujofakawowasa.pdfIn PDF document text
    • http://gpszone.hu/upload/userfiles/file/11834018526.pdfIn PDF document text
    • https://alstar.uz/images/shared/file/pokelowizozolun.pdfIn PDF document text
    • https://chanty.dacola.com/upload/files/mirupuwafelowev.pdfIn PDF document text
    • http://doradcyprawni.com/images/pliki/wuvebonugiga.pdfIn PDF document text
    • http://lecieldesandes.fr/ckfinder/userfiles/files/puvinamaf.pdfIn PDF document text
    • http://chistogood.ru/admin/ckfinder/userfiles/files/42671136526.pdfIn PDF document text
    • https://movingalpsfoundation.ch/userfiles/file/jimeditisudekelu.pdfIn PDF document text
    • http://w-w.cn/isee/pfm/cms/uploadfile/fck/file/8717598836.pdfIn PDF document text
    • https://baoholaodong24.baohohoanglong.com/userfiles/file/sutere.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135328c4d754---7785451734.pdfIn PDF document text
    • http://miskolciharsona.hu/pictures/file/835895355.pdfIn PDF document text
    • http://safiorida.dk/operatori/userfiles/file/11822925912.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/32834819220.pdfIn PDF document text
    • http://marktoby.com/akram/know_news/admin/userfiles/file/84495519517.pdfIn PDF document text
    • https://rireenfrance.com/images/upload/files/sujumobubigekewaz.pdfIn PDF document text
    • https://spherule.org/wp-content/plugins/super-forms/uploads/php/files/o3v25jltt17ev6qjvvueeq0ce7/nikewuzijuvoredi.pdfIn PDF document text
    • https://rpaxis.net/userfiles/file/55275006665.pdfIn PDF document text
    • https://przyklejki.pl/userfiles/xulatisemeradonidana.pdfIn PDF document text
    • http://katachizu.com/img/news/files/26791195231.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=galaxy+note+3+android+10PDF 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_off0000bdf3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDF3 19640 bytes
SHA-256: ee427bfebd8cd10104b1a35427b2d85de89c7c7c41bdf38821e34ae00579c47b
font_01_sfnt_off0000f039.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF039 10672 bytes
SHA-256: 074318836d8651776c67f24f042db9de2d627de2f0d5f92bf893d3e0b60448dc
font_02_sfnt_off000108ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108EE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1