Malicious PDF — malware analysis report

Static analysis result for SHA-256 f81763e7fed444d5…

MALICIOUS

PDF

78.0 KB Created: 2021-07-31 22:35:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 4fd69fedb09310c1a14750be83fa8418 SHA-1: 25c6e1a6a25d952fc666d3dedb66f458ac84892c SHA-256: f81763e7fed444d5106f7a18ba60d451accf35a272b309c84895972498a84e7f
196 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous external PDFs, many hosted on compromised WordPress sites. The heuristic firings indicate a deliberate attempt to create a link farm on disposable hosting, likely to obscure the final malicious destination. ClamAV detection and ML classification confirm the malicious nature of this PDF, which is likely used as a lure to deliver further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://rayanchem.com/d/files/37189669430.pdf In PDF document text
    • http://www.marsagri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d7ec6091df2---zijosasuzafud.pdfIn PDF document text
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/1607ef4332f8ec---vozexigelizaviramopo.pdfIn PDF document text
    • http://jornalespacoaberto.com/app/webroot/datafiles/editor/files/96136171464.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/20829814158.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1607792e7068c3---bawaveruraj.pdfIn PDF document text
    • http://exosportsante.fr/ckfinder/userfiles/files/88692369067.pdfIn PDF document text
    • http://bobmeetin.com/media/galleries/files/31047651845.pdfIn PDF document text
    • https://geneticapanama.com/userfiles/file/gofebeziluxolumuvusaw.pdfIn PDF document text
    • https://www.cfo-search.com/wp-content/plugins/formcraft/file-upload/server/content/files/160919913a675e---najipogemotukifovemusibu.pdfIn PDF document text
    • https://sindicav.com.br/ckeditor/ckfinder/userfiles/files/90772876036.pdfIn PDF document text
    • https://www.accidentinjuryalbuquerque.com/wp-content/plugins/super-forms/uploads/php/files/edl61purtqv34plfgpvfqo74em/sikusagisobozixuvo.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/911kqsrmqal07affg9f32nlnj6/laxenamuguvifop.pdfIn PDF document text
    • http://xn--80aaeiengkwpz6p.xn--p1ai/pub/file/40930407120.pdfIn PDF document text
    • http://pro-elec.ru/ckfinder/userfiles/files/76864735912.pdfIn PDF document text
    • http://associatedreclaimed.com/userfiles/files/jelad.pdfIn PDF document text
    • https://shipnhanh247.vn/asset/files/35665635741.pdfIn PDF document text
    • https://asset-books.com/userfiles/file/27333330101.pdfIn PDF document text
    • https://arrayamed.com/userfiles/file/83989647657.pdfIn PDF document text
    • https://www.expoagrogto.com/wp-content/plugins/super-forms/uploads/php/files/moimf4agcd65i75priudb9olo2/dorelatajuzexunifonake.pdfIn PDF document text
    • http://debnine.net/UserFiles/File/semasemusonumamofoniwij.pdfIn PDF document text
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ca19c37068---78794526162.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=punctuating+sentences+ks2+worksheetPDF 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_off0000c98f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC98F 17288 bytes
SHA-256: 0f13c28b5a82a9205685fb94a1f044a15b0ef84c5c90ec36c75f89044a1263c0
font_01_sfnt_off0000f677.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF677 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010e8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E8E 10864 bytes
SHA-256: 22b66826a6b23f0a9104588f35f5742aedb97ef83ef1f9c9dc9fef7419a17771

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