Malicious PDF — malware analysis report

Static analysis result for SHA-256 21c953eb378ae29f…

MALICIOUS

PDF

76.3 KB Created: 2021-09-11 19:20:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 8ba35311d8eb87d5692d38c319e9625d SHA-1: f4e8ba7fc982fae97fe13a1a5f71412b8e7a7b83 SHA-256: 21c953eb378ae29f6201b96a194e4789738710d52438dc750b291b0b98d0560e
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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 http://pro-group.ru/userfiles/file/98608163109.pdf In PDF document text
    • https://client-sms.com/ckfinder/userfiles/files/fopajulikemet.pdfIn PDF document text
    • http://otestmanager.org/club/data/userfiles/file/20210903215737.pdfIn PDF document text
    • http://lanaecoloridabruzzo.it/userfiles/file/6221120220.pdfIn PDF document text
    • http://webmba.fr/client/logo/file/20692286333.pdfIn PDF document text
    • https://kisikana.hr/UserFiles/files/25304646872.pdfIn PDF document text
    • http://zafirkort.com/uploads/files/gupuz.pdfIn PDF document text
    • https://www.vita-organic.eu/admin/ckfinder/userfiles/files/42652323880.pdfIn PDF document text
    • https://rrr71.ru/upload_picture/gikonikodujufuvuxej.pdfIn PDF document text
    • https://kantankacreative.com/wp-content/plugins/super-forms/uploads/php/files/e63fc74f7c46cc4b99f34f72e41b85ee/burazidibidegatidezite.pdfIn PDF document text
    • https://autotronics.vn/userfiles/file/4416960315.pdfIn PDF document text
    • http://xn--k1akb4c.xn--p1ai/userfiles/file/91044562501.pdfIn PDF document text
    • https://losaltos.com/wysiwygfiles/file/19451326356.pdfIn PDF document text
    • http://mh-gartengestaltung.de/userfiles/file/54656618372.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613204ced6e92---13739178755.pdfIn PDF document text
    • http://structurecreative.com/wp-content/plugins/formcraft/file-upload/server/content/files/161312db42b4ea---zikijapuvodifezaxedes.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/b502c909b28ab02b98a2f0c12e438818/nodimuvex.pdfIn PDF document text
    • https://sydneystudytour.com/accounting/userfiles/file/kenovesifup.pdfIn PDF document text
    • http://ultraljud.nu/bild/files/3196796342.pdfIn PDF document text
    • http://domingo.hu/ckfinder/userfiles/files/kapusetometamolem.pdfIn PDF document text
    • http://pegastelco.com/pictures/files/tinosizuwa.pdfIn PDF document text
    • https://catwalkdogcome.com/editor_upload_image/file/65972248453.pdfIn PDF document text
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/16137637ea3ddf---gomoluwodaxajopija.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=when+does+season+5+my+hero+academia+come+outPDF 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_off0000c49f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC49F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000dcb1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCB1 17644 bytes
SHA-256: 868ca734fe32a475c096d36d8c2894209283e125e163176aacf1464dcbec6b4f
font_02_sfnt_off00010a2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A2E 10932 bytes
SHA-256: 21d7c1b9b1fa86358eef86d1dde2bcce35561439088b23377b9b036b0788c8b4