Malicious PDF — malware analysis report

Static analysis result for SHA-256 acfd4e5dc08eef13…

MALICIOUS

PDF

79.4 KB Created: 2021-09-03 17:27:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 56da1f729955556c2177f26a440cfe45 SHA-1: 1eadaef98dc2263e86b47d2b631ef5ace96c46bb SHA-256: acfd4e5dc08eef13b89be4f7c9521b9f80e9125c380976b7137dc0a0ecfa5da3
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a link farm designed to redirect users to various external websites, disguised as a printable worksheet. Several heuristics indicate the PDF is part of a link farm hosted on disposable or compromised domains, suggesting a phishing or malware distribution attempt. No scripts were extracted, but the embedded URLs are the primary indicators of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • 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://ketchas.ru/uplcv?utm_term=printable+times+table+worksheet PDF link annotation
    • https://www.hotwaterfactory.com.au/wp-content/plugins/super-forms/uploads/php/files/dd6b5931db39987f6eee7d7adf3f9d77/60727042472.pdfIn PDF document text
    • http://quiltingacademy.net/fckeditor/userfiles/file/japibebe.pdfIn PDF document text
    • https://kodeac.com/wp-content/plugins/super-forms/uploads/php/files/0jtludqv7g1nb7918mgi6bq06d/goraxopeboguv.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/09d929b0c5dbaf16810c300300d47209/vimituderawik.pdfIn PDF document text
    • http://turinhotelcompany.com/userfiles/files/bixotag.pdfIn PDF document text
    • https://giorgiosantinelli.it/file/28078314604.pdfIn PDF document text
    • http://boekenwinkelindex.nl/images/uploads/xawudevakakip.pdfIn PDF document text
    • http://www.melloecastro.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c8a2735dbd---4734472723.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1606c9922d35f8---87704124873.pdfIn PDF document text
    • http://ecole.ru/text/images/file/24759710167.pdfIn PDF document text
    • http://averon.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160720325ba280---munupirugupigig.pdfIn PDF document text
    • http://hijoin.hu/editor_up/wavonepitaj.pdfIn PDF document text
    • http://cu-mbc.com/ckfinder/userfiles/files/warudipafi.pdfIn PDF document text
    • http://luyenthidhcanhsat.com/Images_upload/files/xuwokupatew.pdfIn PDF document text
    • https://comptables-publics.fr/userfiles/file/68235658617.pdfIn PDF document text
    • http://www.gunyagder.org.tr/wp-content/plugins/super-forms/uploads/php/files/mbao5nldh7pmhuji4fcq5fht27/jezululajadupevudiwetatul.pdfIn PDF document text
    • https://muratay.nl/userfiles/file/fasojukijo.pdfIn PDF document text
    • https://carea2plus.com/wp-content/plugins/super-forms/uploads/php/files/e309af82d3cef76b0e678cd2a0181187/85395743350.pdfIn PDF document text
    • http://www.driftime.ee/wp-content/plugins/formcraft/file-upload/server/content/files/16094555c3e97d---51444383678.pdfIn PDF document text
    • https://rakowka.pl/userfiles/file/5344144905.pdfIn PDF document text
    • http://fedoro.ru/upload/file/23130276566.pdfIn PDF document text
    • http://mishelik.ru/userfiles/file/zofisewo.pdfIn PDF document text
    • 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_off0000d646.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD646 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ee58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE58 16064 bytes
SHA-256: c09269a13ad6d927a569dda3c1f492ca8cb8a1743ad76e44e9fab1ea3de7fdf3
font_02_sfnt_off000117c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117C7 10692 bytes
SHA-256: 3d8ef82b798f20dc5df1ccdb0f5e3c0dfe097633176c7d2ce83251e27dadca13