Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef234f24e66de31c…

MALICIOUS

PDF

80.5 KB Created: 2021-09-07 15:47:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 154f1c398eee4e1ecb63432db9bcad57 SHA-1: 111e01103824677f5cf61b1aa60a252a6bcf3bc0 SHA-256: ef234f24e66de31c7f971cc6d03574ab0367dd0f7de9c19176347dc5f0ddd204
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a non-clustered link farm on disposable hosting, and the PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristic further supports the use of compromised infrastructure. While no scripts were explicitly extracted, the presence of embedded URLs and the nature of the heuristics strongly suggest an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://deconkhoemanh.com/wp-content/plugins/super-forms/uploads/php/files/jgu9j7j3j44cavcp1lvj0ai5or/42817807608.pdf In PDF document text
    • https://www.ccps.mx/wp-content/plugins/super-forms/uploads/php/files/202b8b769bfe7ec42d36071142aaac75/pimowikukinaja.pdfIn PDF document text
    • http://beerskiboot.com/img/upload/file/kogajibefizenupos.pdfIn PDF document text
    • https://christianboudreau.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608870da02ed8---9950821536.pdfIn PDF document text
    • https://hyundainhapkhau.vn/upload/files/xadisesu.pdfIn PDF document text
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c986148a8f1---loxakaberabitos.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/48331303090.pdfIn PDF document text
    • https://vernadoc.com/wp-content/plugins/super-forms/uploads/php/files/92ffb8fb72e165edf0e117cfa748267c/19264177539.pdfIn PDF document text
    • https://smarttactic.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16107766e47b43---rosazemebovevagefajutes.pdfIn PDF document text
    • http://ibtaker.ps/userfiles/file/8901943846.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608f71a62813f---87519472277.pdfIn PDF document text
    • https://www.waterlooarmsnewforest.co.uk/wp-content/plugins/super-forms/uploads/php/files/e14fbf99f5f577d67de36009592d1a92/72909688488.pdfIn PDF document text
    • https://iqmuseum.mn/uploads/files/belagexepobusazudokifun.pdfIn PDF document text
    • http://www.bewegeninarnhem.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160b7fc1c113c5---gupewuf.pdfIn PDF document text
    • https://krainaogrodow.eu/zdjecia/fck/file/24318077096.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130a7df37615---78519823369.pdfIn PDF document text
    • https://www.techsrollout.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b64870a4b3c---61113629303.pdfIn PDF document text
    • http://lateonsettay-sachs.org/userfiles/file/49543440246.pdfIn PDF document text
    • http://rethabise.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160a6db3418fe6---sitalujazaziz.pdfIn PDF document text
    • http://bisenzia.it/userfiles/files/42003512158.pdfIn PDF document text
    • https://www.gpaci.org.br/cms/ckfinder/userfiles/files/fedofolug.pdfIn PDF document text
    • https://advancedbusiness.co/wp-content/plugins/super-forms/uploads/php/files/f59b6034d85e97ff512704c7ca3a870b/xeteniwuvijukuzemajo.pdfIn PDF document text
    • https://www.ikedatosou.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f9b23a4c1b---37936845413.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=patofisiologi+bronkopneumonia+anak+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_off0000d612.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD612 16804 bytes
SHA-256: f9d95af7c6971c210e44dcdbe09d807a42ec24cb53f02694de10ae143177cf44
font_01_sfnt_off0001020c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1020C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011a23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A23 11176 bytes
SHA-256: c5d3877533181ea2f932f82b31b8372a1cd53c7d518f00f6fddeac7b9c030278

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