Malicious PDF — malware analysis report

Static analysis result for SHA-256 83575d38c39ff406…

MALICIOUS

PDF

83.7 KB Created: 2021-09-14 11:26:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 5039f83460da121b40d68840c899d6af SHA-1: 670852b14393e6e1da88328beda8674112b7d706 SHA-256: 83575d38c39ff4063ff5fcfebf340ee0dd293f9a5b6a6258e04392d329c17b58
96 Risk Score

Malware Insights

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

The ML classifier strongly indicated maliciousness, and heuristics identified the PDF as a link farm pointing to compromised websites and disposable domains. The document body was unreadable, but the presence of numerous external links suggests a lure to external malicious content, potentially for phishing or SEO abuse. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://ukonlinedirect.com/userfiles/files/4927493004.pdf In PDF document text
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/f2c8ad7738407a8db5219ef96e0fabfc/naxabikozofu.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136bec06dd4c---72009130863.pdfIn PDF document text
    • http://kaupa.cz/userfiles/file/niropisotuwoxip.pdfIn PDF document text
    • https://magnettoptan.com/upload/ckfinder/files/milejuremonup.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/1613bedf02a84b---milefisexajunud.pdfIn PDF document text
    • http://bycongroup.com/UserFiles/file/80729477437.pdfIn PDF document text
    • http://irfanmakina.com/depo/sayfaresim/file/2841336374.pdfIn PDF document text
    • https://efficimm.fr/userfiles/files/25630626345.pdfIn PDF document text
    • https://hattoco.vn/images/ckeditor/files/vuvuzigemibe.pdfIn PDF document text
    • http://kasintorn.com/images/upload/files/novotivubilogonovamux.pdfIn PDF document text
    • https://blokhol.com/upload/files/82256708016.pdfIn PDF document text
    • https://cokhivietuc.com/img-vietuc/files/91780066082.pdfIn PDF document text
    • http://daiichihr.com/uploads/news_file/nudonumelomarageketetima.pdfIn PDF document text
    • https://marciasmithconsulting.com/wp-content/plugins/super-forms/uploads/php/files/a3716fcb9434c8a881c8bdd40984fe54/82937397450.pdfIn PDF document text
    • https://fonixkoncert.hu/upload/file/91832536780.pdfIn PDF document text
    • https://anmimar.com/royal/userfiles/file/ditezekeluko.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1612f76fb80ad6---daxizosiw.pdfIn PDF document text
    • http://vpecargo.com/userfiles/file/fufokijerefonojakuwoxixu.pdfIn PDF document text
    • http://www.peritaonline.es/ckfinder/userfiles/files/11456796668.pdfIn PDF document text
    • https://client-sms.com/ckfinder/userfiles/files/5517941348.pdfIn PDF document text
    • http://gloteckr.com/upload/editor/file/xufeletuz.pdfIn PDF document text
    • https://ww150001.linebot.net/upfile/files/20210914122153.pdfIn PDF document text
    • https://pcetravel.com/files/file/82656716734.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=contacts+from+iphone+to+androidPDF 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_off0000e1f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1F1 10868 bytes
SHA-256: c30419557f050ed69fe1ad457eb2b011b0150b06991635ad2e4960d3aaaa8a40
font_01_sfnt_off0000fae4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAE4 17844 bytes
SHA-256: 66a872b53d3536fc27e7099dd28ef9c56db8dcbcaa480437256a9dc7fe8366d7
font_02_sfnt_off000128eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128EB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1