Malicious PDF — malware analysis report

Static analysis result for SHA-256 99bb4ceb5e2a0968…

MALICIOUS

PDF

73.1 KB Created: 2021-06-14 11:55:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: a4d5eb94299999d1e0ee8a52b7744817 SHA-1: fb6ef15735bd82a9f590491aaa26371180c279df SHA-256: 99bb4ceb5e2a0968755a1d61d2e699d525bd95f5f047468865adae716d43ac37
144 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.007 JavaScript

The PDF document contains heuristics indicating it is a link farm and uses a social engineering lure to trick users into installing a browser extension or update. The embedded URL 'https://coretry.ru/uplcv?utm_term=gta+5+download+apk+no+human+verification' suggests a lure related to game downloads, which is a common tactic for malware distribution. The ML classifier strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://coretry.ru/uplcv?utm_term=gta+5+download+apk+no+human+verification PDF link annotation
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aef931ecc04---17791793023.pdfIn PDF document text
    • https://martybermanassociates.com/wp-content/plugins/super-forms/uploads/php/files/09168ee37d58f303ef4d8ed86df4b12b/94511090042.pdfIn PDF document text
    • http://ordinate-ltd.com/file_media/file_image/file/gemugaretogu.pdfIn PDF document text
    • http://www.platformliften.info/wp-content/plugins/formcraft/file-upload/server/content/files/1608f037ca1a0a---68740018464.pdfIn PDF document text
    • https://oneremote.ru/wp-content/plugins/super-forms/uploads/php/files/3e456911e049be3d088422f67b9fb536/satovuz.pdfIn PDF document text
    • http://cs-web-design.de/ablage/userfiles/files/83964463683.pdfIn PDF document text
    • http://mesterek.net/tmp/rubezomumo.pdfIn PDF document text
    • https://avantkart.com/wp-content/plugins/super-forms/uploads/php/files/k8699m90g3v4b6glips7p1dqr6/82524576022.pdfIn PDF document text
    • https://www.visitrwanda.com/wp-content/plugins/super-forms/uploads/php/files/de9053d4d189537bb65eb91c961e13bb/89852476451.pdfIn PDF document text
    • http://sanitaerprofi.ch/fckeditor/editor/images/file/nevudipupunivipuxe.pdfIn PDF document text
    • http://maxidmum.com/images/upload/fck/file/bojebuw.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/18030501416.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dfb1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFB1 5588 bytes
SHA-256: adbf34b294354f40eee1a7dd160e5cfc70df48e52d4a0a28905556a2e9838c2a
font_01_sfnt_off0000f2af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2AF 10944 bytes
SHA-256: acbd61d4bec2bf689a3ec6d00a0483efb1a9db0945b7276bc6b46d7b0f2f9bde

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