Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef0004f5d7a37641…

MALICIOUS

PDF

89.3 KB Created: 2021-09-15 17:10:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: bae0d7a034f4fc75d824ce5ec09f9b39 SHA-1: 200569b3bc63d8e16593b3a41c97c2b462d0feea SHA-256: ef0004f5d7a376414ffe4214cc536956efe156a48e8ce6b29cae9926409427e9
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many embedded URLs pointing to potentially compromised CMS upload storage or disposable hosting. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, suggesting the primary function is to host links rather than display information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://dennismaloney.ca/upload/editor/file/vutokoz.pdf In PDF document text
    • https://tcufroghouses.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f5cb14905b---jufimudimowodovuderezito.pdfIn PDF document text
    • http://prodottoitalia.eu/userfiles/files/15642396159.pdfIn PDF document text
    • http://coinproject.com/userfiles/image/file/lukefasojekevibadepazo.pdfIn PDF document text
    • http://xn--80aafjbaeihgganggf9ajkncugh2a.xn--p1ai/pict/file/25004481926.pdfIn PDF document text
    • https://phoenixknights.co.uk/wp-content/plugins/super-forms/uploads/php/files/70c3928c093b8a520177bc0ff2f35848/wifanuroribavivi.pdfIn PDF document text
    • http://goldmustang.com/files/files/leveleresawoj.pdfIn PDF document text
    • http://alarcon-v.com/editor_upload_image/file/52162476656.pdfIn PDF document text
    • http://gemcom.org/userfiles/file/niguxaxinoworafemimu.pdfIn PDF document text
    • http://gitimohammadilakhimpur.org/ckfinder/userfiles/files/desifovojavufok.pdfIn PDF document text
    • https://www.formwork.co.uk/wp-content/plugins/super-forms/uploads/php/files/aucbuc5g1o3aol073e74s9kpbj/vuwuvil.pdfIn PDF document text
    • https://mediabandit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a0581c6c25---53864522762.pdfIn PDF document text
    • http://liceoadultos.juniorcollege.cl/userfiles/files/xemataviwure.pdfIn PDF document text
    • http://bsp-plovdiv.org/ckfinder/userfiles/files/zunikupobuwor.pdfIn PDF document text
    • https://yodishit.com/uploads/userfiles/file/sojawazi.pdfIn PDF document text
    • https://foulardfotografando.it/file/zevuxomalegoxidipuse.pdfIn PDF document text
    • http://dytac.hk/userfiles/35740831996.pdfIn PDF document text
    • http://cathugo-catamarans.de/res/wysiwyg/file/vumivodama.pdfIn PDF document text
    • http://househouse.it/userfiles/files/36769123503.pdfIn PDF document text
    • http://www.fdconsult.qa/public/uploads/cms_files/41204907251.pdfIn PDF document text
    • http://analhospital.net/file/files/xudumekasexagalupame.pdfIn PDF document text
    • https://vili-al.com/uploads/wysiwyg/files/32942479352.pdfIn PDF document text
    • https://zapcdn.space/web/img/podborky/files/95826550047.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=headhunters+io+mod+apkPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d817.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD817 21724 bytes
SHA-256: 490ecd399406a127feb303148e4e6adb6c17ea5c6c17660fae4bfc9ffc50f74d
font_01_sfnt_off000110ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110CA 10792 bytes
SHA-256: 49cf1cd1e46f09db3fbb18c53ae723aa83b773446f2e487b1633f094aeb97dde
font_02_sfnt_off0001295a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1295A 16148 bytes
SHA-256: b17e3c388ca520c70044df51a505a8c8de3d1ca9b2e495c629779bc8d31aca59
font_03_sfnt_off00013ee9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13EE9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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