Malicious PDF — malware analysis report

Static analysis result for SHA-256 911841007fdb79ed…

MALICIOUS

PDF

83.9 KB Created: 2021-10-07 21:32:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 87605fb8982f692ae9b6731ea4a1f033 SHA-1: e770a38bbc7d2fe236e13b15a8f2c44b9a0e0637 SHA-256: 911841007fdb79edcb18a1a7678fc539a97a7cf38ad14d9d8402eafcaa1bf04d
96 Risk Score

Malware Insights

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

The PDF file contains a link farm, with numerous embedded URLs pointing to other PDF files hosted on various domains. Several heuristics indicate this is a link farm on disposable or compromised hosting, likely intended to manipulate search engine results or distribute malicious content. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a 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://starfoil-mail.nl/uploads/wysiwyg/72775950086.pdf In PDF document text
    • http://dxczx.com/ckfinder/userfiles/files/20210917_144353.pdfIn PDF document text
    • http://icsbc.ru/fuploader/file/95393754335.pdfIn PDF document text
    • https://luckyfood.itweald.com/uploads/files/6145f40bd8cde.pdfIn PDF document text
    • https://bringem.de/wp-content/plugins/super-forms/uploads/php/files/9e7e8cdec37475f891f1876ae1777a42/basitok.pdfIn PDF document text
    • https://thuaphatlaihoanghuy.com/uploads/files/51789308561.pdfIn PDF document text
    • http://srtcivilnorth.com/ckeditor_file/files/tapikurewo.pdfIn PDF document text
    • http://asesoriagarpe.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614308502a187---48716909908.pdfIn PDF document text
    • http://spbi.cz/res/file/fenikowogugovasefupu.pdfIn PDF document text
    • http://ourpreferred.com/userfiles/files/pisebizidetebap.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/bf6727448d671e90a62b9281253395a5/toxorevukutuvobategevu.pdfIn PDF document text
    • http://www.benvenutialmare.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614376d8aa503---67758250739.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614573a5e3fab---zejawumafowitimim.pdfIn PDF document text
    • https://ipssecurityconsultants.com/ckfinder/userfiles/files/59007669385.pdfIn PDF document text
    • https://www.sexualaufklaerung-schule.ch/ck/ckfinder/userfiles/files/kezugufure.pdfIn PDF document text
    • http://zdrowejaja.com/Upload/file/89135841703.pdfIn PDF document text
    • http://weiddy.com/uploads/files/202109091929342528.pdfIn PDF document text
    • http://www.parkwaytransplant.com/media_upload/upload/files/xonodenatoxidulumebo.pdfIn PDF document text
    • http://business-plan-capalpha.fr/mbp/upload/images/images/upload/ckfinder/37344235246.pdfIn PDF document text
    • https://ladangmimpi2.com/contents/files/xugepesafuxepusano.pdfIn PDF document text
    • http://imhyuk.com/imhyukeditor/userfile/file/35948717547.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/vixugorafapiganafirekoxut.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=best+websites+to+learn+arabic+for+freePDF 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_off0000ddc7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDC7 19844 bytes
SHA-256: deb3db82af055332ba282c23ebd570965f774b77a286b1bfd16b1bb7d38a8e33
font_01_sfnt_off00011165.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11165 10608 bytes
SHA-256: a0676257195fc0209c28ad08e7d90d2874f2cb1fa3a336206338411b138dfe3f
font_02_sfnt_off000129e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129E4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1