Malicious PDF — malware analysis report

Static analysis result for SHA-256 50a4175c1ee3361b…

MALICIOUS

PDF

85.0 KB Created: 2021-09-17 17:33:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 3313b63441191c4f6e6ab0d0bfb014d9 SHA-1: df9ad91a04e7e91aa1c7a27610a8586cebdde2e7 SHA-256: 50a4175c1ee3361bdf7fc74df47a4d8ece406b7593d71092145d75ce23d09f1c
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to compromised CMS upload directories, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly support its malicious nature. The file's purpose appears to be redirecting users to potentially harmful external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://krassimirtaskov.com/userfiles/files/16323081152.pdf In PDF document text
    • http://geasit.it/userfiles/files/61939857755.pdfIn PDF document text
    • http://go-pxl.com/uploads/files/91988061733.pdfIn PDF document text
    • http://handlpc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/nojejoziwefuresi.pdfIn PDF document text
    • https://championsforchildren.org/wp-content/plugins/super-forms/uploads/php/files/6a9b4af69b95d93ce0bb4ca5f099977e/mubovelu.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b162c163bb.pdfIn PDF document text
    • https://homestayhoian.thamtuddt.com/uploads/image/files/7000112775.pdfIn PDF document text
    • http://www.bewegeninarnhem.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161419fc0a3a45---15861542046.pdfIn PDF document text
    • https://newsale.linyn.mobi/upload/ckeditor/pages/files/vogesewuvolomotafata.pdfIn PDF document text
    • https://bomnuocebara.com/quangbasanpham/app/webroot/upload/image/files/57080826701.pdfIn PDF document text
    • http://wm-meyer.de/meyer/admin/editor/ckfinder/userfiles/files/8499411775.pdfIn PDF document text
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/op23avi6d7ub1329vppv2v0iku/ruzokoxiduf.pdfIn PDF document text
    • http://sinojjacob.com/userfiles/file/74762725500.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f1b535abe1---mufej.pdfIn PDF document text
    • http://marcth.pl/media/fck/file/tutawodakuku.pdfIn PDF document text
    • http://hydrogears.com/survey/userfiles/files/2094030984.pdfIn PDF document text
    • https://worldmedglobal.com/userfiles/files/20009450866.pdfIn PDF document text
    • https://peoplehelppeople.net/uploads/File/83440378972.pdfIn PDF document text
    • http://baovethanglongmb.com/upload/files/42281305474.pdfIn PDF document text
    • http://loscogliodifavignana.it/userfiles/files/wukupuxapisipenam.pdfIn PDF document text
    • http://abw10thstreetne.com/uploads/files/maziwunewuvexowebekur.pdfIn PDF document text
    • http://xn--80akazwaeiw.xn--p1ai/editorfiles/file/dorub.pdfIn PDF document text
    • http://ttworld.hu/uploads/content_files/files/28253563267.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=ielts+writing+task+2+book+pdfPDF 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_off0000e748.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE748 11064 bytes
SHA-256: 61e0a74f785ff1e9d2591e482ff0ab1ac0bdda38daf409d32ffb5d437f35d557
font_01_sfnt_off000100dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000118ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118EF 17568 bytes
SHA-256: fa18098dfdd3c1b8fe21567b1834e7c9e71cbca0c1da2f0ae98a692210e2ea41