Malicious PDF — malware analysis report

Static analysis result for SHA-256 8cb6a9a3715b4e05…

MALICIOUS

PDF

77.3 KB Created: 2021-09-17 05:36:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 42f0da9221f6e06b93bc6e2be88c2bba SHA-1: 0bf69a8ad3d7df62f3c647e5c3654865dc998d51 SHA-256: 8cb6a9a3715b4e05aac04ff6dfe1fbf24fc9f89d2ac8ad894c0fd58eae85a531
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF contains a link farm pointing to compromised WordPress sites, which in turn host other PDF files. This suggests a multi-stage attack, likely for phishing or to deliver a secondary payload. The presence of numerous external URIs and the compromised CMS upload links are key indicators of this malicious infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://philabc.ru/uplcv?utm_term=one+night+only+eng+sub PDF link annotation
    • https://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140167239437---kugeb.pdfIn PDF document text
    • http://www.lnk-creation.fr/upload/file/37688954165.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131ff8e9f4fb---5807057798.pdfIn PDF document text
    • https://www.helpfulhunks.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613a501405598---79378944647.pdfIn PDF document text
    • http://ukrfirework.com/images/file/20272270140.pdfIn PDF document text
    • http://ohana1bbq.com/uploads/files/kajitalapeziwekuzitudesur.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613ff032c748b---labegijerupiwerusig.pdfIn PDF document text
    • http://kbcsisa.com/upload/fckeditor/file/28461351204.pdfIn PDF document text
    • http://techcessgroups.com/userfiles/file/kigegezimagefubofukaxef.pdfIn PDF document text
    • http://qiuyutv.com/userfiles/files/20210915094431.pdfIn PDF document text
    • http://mcenterdk.ru/fck_editor_files/files/xipijafuwob.pdfIn PDF document text
    • http://jungam21.com/upfiles/file/1631030387.pdfIn PDF document text
    • http://architettotamborra.eu/userfiles/files/kexisimer.pdfIn PDF document text
    • http://naturestuff.nl/siteimages/file/tavafetifid.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/16140f7bcac7be---17353385778.pdfIn PDF document text
    • http://nuyewpilot.academy/wp-content/plugins/super-forms/uploads/php/files/362138754191b2507230b6c625a5c103/2994037029.pdfIn PDF document text
    • http://newbusan.net/FileData/ckfinder/files/20210914_FA8AE47726C08B54.pdfIn PDF document text
    • http://kursadowicz.pl/Upload/file/79084992415.pdfIn PDF document text
    • http://hbaoge.com/upload/files/bezaregelep.pdfIn PDF document text
    • https://maintogelonline2.com/contents/files/14160909802.pdfIn PDF document text
    • http://sushiloverca.com/uploads/files/jimoxoxiponasadadafugu.pdfIn PDF document text
    • http://thaifilmind.com/UserFiles/file/94809328788.pdfIn PDF document text
    • https://alharithiforcameras.com/ckfinder/userfiles/files/wobajorakakodafakemaza.pdfIn PDF document text
    • http://xn--80aap0abfiql8h.xn--p1ai/admin/ckfinder/userfiles/files/mofexow.pdfIn 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://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_off0000bed0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBED0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d6e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6E7 10504 bytes
SHA-256: fb23d18bcd91b5362be33fcaa2deeaea97e9a3ffc22dfe337627b9e72c7d7cbb
font_02_sfnt_off0000eec6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEC6 22228 bytes
SHA-256: 079583e7df56bcb96aa84f48c7014c90480133b6700af2425c87890cf0c84674