Malicious PDF — malware analysis report

Static analysis result for SHA-256 988849ec87f3e956…

MALICIOUS

PDF

81.4 KB Created: 2021-06-24 02:14:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: cd42aafa1d7d423e6a7887686be7f1df SHA-1: ebbace353cd68a91e3b48f54bf171eea1a88f1d2 SHA-256: 988849ec87f3e956561ae431916897552d033448f7150359763d43a48a990855
156 Risk Score

Malware Insights

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

This PDF was flagged by ClamAV as a phishing trojan and by an ML classifier as malicious. It functions as a link farm, with numerous embedded URLs pointing to compromised WordPress upload directories and other disposable hosting. These links likely lead to further malicious content or phishing pages, indicating a multi-stage attack. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://www.marbelitesa.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1606d500f6640d---6556040503.pdf In PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/s03v3d62jg1qm0qs760g0gv4ej/36474220093.pdfIn PDF document text
    • http://asahiru-ban.com/files/files/solejas.pdfIn PDF document text
    • https://www.skyline-recruiting.com/wp-content/plugins/super-forms/uploads/php/files/44fb14821c5b5f5d0c4f9e4eeb0d6897/62750140137.pdfIn PDF document text
    • http://subventionsbetrug.de/wp-content/plugins/super-forms/uploads/php/files/hen84k7jakjgk10d5r08quma31/pegedi.pdfIn PDF document text
    • https://hitourkorea.com/FileData/ckfinder/files/20210620_E5E024F9B798F1BC.pdfIn PDF document text
    • http://www.photobreak.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160946fbe35d55---22547383403.pdfIn PDF document text
    • http://www.bestlifepolicy.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160b6376c40d51---mikajomobusorelafuj.pdfIn PDF document text
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/r8ds2a8i37sf296uf6o6fhi6bh/98440055196.pdfIn PDF document text
    • https://www.areatransfers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098f9e58969d---80077673666.pdfIn PDF document text
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/p2ted0am52rark3e5vfjk623bb/jekedelewaxiwi.pdfIn PDF document text
    • https://www.foundationofhope.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607f7d7458bcf---66682614217.pdfIn PDF document text
    • http://www.itbaloch.com/wp-content/plugins/formcraft/file-upload/server/content/files/160897e1759d14---sewenifovegivelokalozajip.pdfIn PDF document text
    • https://leunamgroup.com/wp-content/plugins/super-forms/uploads/php/files/592653f4b052d376dd6c549497460618/kumisiruki.pdfIn PDF document text
    • https://mmagame.com/userfiles/file/44442221315.pdfIn PDF document text
    • http://mispuntossaga.com/campannas/file/nilufufavinivujax.pdfIn PDF document text
    • https://flvirginia.com/wp-content/plugins/super-forms/uploads/php/files/c7e7978bd7f3092ee86c1bca90a07dec/sewaseve.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=biorad+t100+thermal+cycler+manualPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fa7f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA7F 5348 bytes
SHA-256: 6f5856d7ec4ebf8649adc9affa8cfac7e24e1609720e959bbeffa4c2bfdfe256
font_01_sfnt_off00010c8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C8E 13868 bytes
SHA-256: 5e0d1a170917697332bcddefbd9c54c8ca65711545013061ade8bd3c1ba0e412