Malicious PDF — malware analysis report

Static analysis result for SHA-256 e4158760dfac1f51…

MALICIOUS

PDF

86.0 KB Created: 2021-07-28 06:14:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 65055091ac5a5253e6a06848db1faae6 SHA-1: 3ff4ac3ee50d87942003f081fd7b9d1bdbdfef5e SHA-256: e4158760dfac1f51cf45a7d3b3af1cef16d703ff8a2aa97d71634a745357c79e
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a high-confidence ML classifier and ClamAV detection. It functions as a link farm, directing users to numerous external URLs, many of which are hosted on compromised CMS uploads or disposable domains. The primary purpose appears to be directing users to potentially malicious or phishing websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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://linhngapt.vn/upload/files/77254069902.pdf In PDF document text
    • http://dollreunion2020.com/clients/4/43/4392dc7a9e9236654a628da0af121bbb/File/24400835020.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/lf613v9uk31vk9jbua1b72keqo/97700128436.pdfIn PDF document text
    • http://ok-poland.com/userfiles/file/6323603570.pdfIn PDF document text
    • http://geology.ie/wp-content/plugins/formcraft/file-upload/server/content/files/160c5b741bd25a---35683609646.pdfIn PDF document text
    • https://www.lokalesichtbarkeit.de/wp-content/plugins/super-forms/uploads/php/files/l2h2m531thvsoff06i36t2lj0c/61695533275.pdfIn PDF document text
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/vatudopuzupog.pdfIn PDF document text
    • https://cornerstonelaw.eu/userfiles//file/45988102406.pdfIn PDF document text
    • http://backupcenters.com/userfiles/file/10692976984.pdfIn PDF document text
    • http://hoondb.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608227b8ee9fd---xolav.pdfIn PDF document text
    • http://abaj.cz/UserFiles/File/60306550592.pdfIn PDF document text
    • http://www.mustwalge.ee/data/content/files/zorugumigijububipeg.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160839f8173189---11281605553.pdfIn PDF document text
    • http://myappartement.de/web/editor/files/91084012927.pdfIn PDF document text
    • http://gayaarchi.com/userfiles/file/20210724213221.pdfIn PDF document text
    • http://www.tenniscanberra.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16082500e48169---26801962517.pdfIn PDF document text
    • http://augustaelectricalwork.com/editorData/file/51429427992.pdfIn PDF document text
    • http://coimbra.hu/uploads/ckfinder/userfiles/files/fafazekus.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/okhse917oq6i22s20p3g0kllfd/57949641525.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16100c12517f55---8058972016.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=is+fancy+feast+wet+food+good+for+catsPDF 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_off0000ec8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC8B 10664 bytes
SHA-256: 12da3088e06a4b90a915706a4099014ecc41a1282f55002d91a3dd23cf15d2ef
font_01_sfnt_off000104ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104FF 17460 bytes
SHA-256: 56984455c87663af756d21035140bb6841b07e666be69dadc6b06ccf7c3923d6
font_02_sfnt_off00013295.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13295 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1