Malicious PDF — malware analysis report

Static analysis result for SHA-256 66cf105000de49ef…

MALICIOUS

PDF

78.7 KB Created: 2021-09-15 14:50:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: aa4b688f091249abcfec782445b122a7 SHA-1: 6204fbe8c195a5bdb97e62428be1bc4b97018ed8 SHA-256: 66cf105000de49ef19ac73444f1d72c6ed1c222b69ac9ece75b9d5c3f86f8f22
156 Risk Score

Malware Insights

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

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 disposable hosting or compromised CMS upload directories, suggesting a link farm designed to redirect users to phishing or malicious sites. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a non-clustered link farm on disposable hosting, and the presence of 'utm_term' parameters suggests SEO manipulation for malicious purposes. The primary attack pattern involves tricking users into clicking these links, likely under the guise of downloading security software.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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://chcial.ru/uplcv?utm_term=pdf+security+remover+software PDF link annotation
    • https://brincandoeaprendendo.com/fotosempresa/files/37305219938.pdfIn PDF document text
    • http://bhk-aindling.com/userfiles/files/41462825807.pdfIn PDF document text
    • http://xn--e1aazeoc7d.xn--p1ai/images/shared/file/sapapovuraxe.pdfIn PDF document text
    • http://infas.cz/images/wiswig/file/32693451789.pdfIn PDF document text
    • http://www.hj-bouwt.be/wp-content/plugins/formcraft/file-upload/server/content/files/161308d1f036b8---94921307424.pdfIn PDF document text
    • http://evrokomplekt.ru/userfiles/file/joziduwubirafedadup.pdfIn PDF document text
    • http://colorfulmedia.de/fotki/fotki/file/15211805088.pdfIn PDF document text
    • https://renault-service.com/userfiles/kokolebizu.pdfIn PDF document text
    • http://matchedtubes.de/userfiles/file/74955581304.pdfIn PDF document text
    • http://festacreativita.org/userfiles/file/poronufakezofaminebak.pdfIn PDF document text
    • https://hotellemaritime.com/hotel/upload/files/juzabefijemaga.pdfIn PDF document text
    • https://www.cfo-search.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613325baaadf2---zaxovatel.pdfIn PDF document text
    • http://fkjz.cn/upload/files/2021/09/202109011625293693.pdfIn PDF document text
    • http://eyela.kr/uploadfile/fckeditor/file/66220120615.pdfIn PDF document text
    • https://www.mobytec.com.br/mobytec/wp-content/plugins/formcraft/file-upload/server/content/files/1613abb7865413---xokewujopulo.pdfIn PDF document text
    • https://xnkvinatimex.com/uploads/files/13024295409.pdfIn PDF document text
    • https://www.mediawerf.nl/bundles/store24backoffice/ckfinder/userfiles/files/41536580284.pdfIn PDF document text
    • http://digitalpolicycouncil.com/imagenes/file/16973522310.pdfIn PDF document text
    • http://interiorconsignments.com/media/file/rurukigugaki.pdfIn PDF document text
    • http://splhardware.com/UploadFile/file/2021090422002673499.pdfIn PDF document text
    • http://sameiroeventos.pt/ficheiros/55682624325.pdfIn PDF document text
    • http://szyqjsj.com/UploadFile/file/20210902233627395.pdfIn PDF document text
    • http://pivotal-technologies.com/userfiles/file/tefan.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130ef44a4247---febexux.pdfIn PDF document text
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/786abec057478af0c7bdf0f6e3638688/38030426996.pdfIn PDF document text
    • https://stopserv.ru/files/file/17227548596.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_off0000d1e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1E1 10856 bytes
SHA-256: 6e1550c02470b00722702581f8b964cea80f82a8e985d4cc1a79ed923332bbc8
font_01_sfnt_off0000eb20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB20 16284 bytes
SHA-256: c4d097d8def3a43541ce1c89c82d4a4af45a1e85ab53af789c452b9db894c49b
font_02_sfnt_off00011516.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11516 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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