Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5cc9f10afd0bf6f…

MALICIOUS

PDF

87.2 KB Created: 2021-09-03 01:42:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 237d15cefc02951fc7ec0c608b1927a8 SHA-1: ae64cf41d841dec25dcaacb5252e0ef48401ef6e SHA-256: a5cc9f10afd0bf6fafdb7f294a85f4a84bc2ef9e6e92396b06d6cf2e7f6c44c6
156 Risk Score

Malware Insights

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

The PDF was identified as malicious by ClamAV and an ML classifier, indicating it likely exploits vulnerabilities or employs phishing techniques. It functions as a link farm, directing users to multiple compromised WordPress upload directories and other domains hosting further PDF files, suggesting a multi-stage attack. The presence of numerous external URIs and the 'link farm' heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://amthanhanhsangchinhhang.vn/upload/files/lekoruxukifaxalabutegovi.pdf In PDF document text
    • https://extremetour74.ru/wp-content/plugins/super-forms/uploads/php/files/dabcea8434f0789bac5d6b22efee7d8f/tixolud.pdfIn PDF document text
    • https://mithermomix.com.mx/wp-content/plugins/super-forms/uploads/php/files/93dffec4991954a099a055ae5e097c95/70149537169.pdfIn PDF document text
    • http://www.sunargrup.com.tr/wp-content/plugins/super-forms/uploads/php/files/3kc6qv7uugiu99cq1o0vfjo7k4/72112321605.pdfIn PDF document text
    • https://yingzhaoliuart.com/upload/file/17334912116.pdfIn PDF document text
    • http://thessalonikiflights.com/files/files/wilonekoligokub.pdfIn PDF document text
    • http://classtool.info/upload/files/soraf.pdfIn PDF document text
    • http://albatrossmrn.com/konadnew/userfiles/file/wizazabimefuna.pdfIn PDF document text
    • http://lottfamilyreunion.com/clients/878857/File/saxibo.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/160ff0acb1101e---wumopafatapisuladafa.pdfIn PDF document text
    • https://himalmanpower.com/ckfinder/userfiles/files/23928711916.pdfIn PDF document text
    • https://xn----8sbcehyodmtf1czh.xn--p1ai/userfiles/file/41547617882.pdfIn PDF document text
    • https://fleschimmo.lu/userfiles/files/doxaru.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1606f6260679a2---14510774610.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bda7b019162---dagisasitutukuxesa.pdfIn PDF document text
    • http://vip-cond.ru/userfiles/file/84746317645.pdfIn PDF document text
    • http://bigdoughpizza.com/uploads/files/kezanupazebugukigu.pdfIn PDF document text
    • https://www.aifimm.it/admin/inc/ckfinder/userfiles/files/18774817433.pdfIn PDF document text
    • https://mytekas.com/UserFiles/file/dusaxefawopobevava.pdfIn PDF document text
    • http://shinserviceodi.ru/wp-content/plugins/super-forms/uploads/php/files/5e7e5a5beb5a4ff77a3842b7ee6c21c1/kukubinurib.pdfIn PDF document text
    • http://fedoro.ru/upload/file/58408563758.pdfIn PDF document text
    • http://maxgear.cz/webpagebuilder/ckfinder/userfiles/files/64638794756.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/r84f38bvvu1k5ksi1g7vfrbka2/17337211573.pdfIn PDF document text
    • https://artlabjo.com/userfiles/file/56010466267.pdfIn PDF document text
    • https://menu2uplus.com/images/file/11569906791.pdfIn PDF document text
    • https://angkoronetour.com/userfiles/file/12310314891.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=collecting+rocks+gems+and+minerals+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_off0000ed77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED77 11084 bytes
SHA-256: 450963267ddbf122a4a925cca154df9bbe722cc5117a49ac18c6721aba70e19a
font_01_sfnt_off0001071c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1071C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011f2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F2E 18468 bytes
SHA-256: bdbd6b4ab5ff462b23285bbc89aee466ec56c4412eaac0714986a6de4d266105