Malicious PDF — malware analysis report

Static analysis result for SHA-256 f31c985f422bcdbd…

MALICIOUS

PDF

79.5 KB Created: 2021-09-18 10:48:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 50f9ee97a18f7de39aa2aacc52f7d04e SHA-1: 0d736ba4cd39cc08a75aa6a77881a9c6aea9466d SHA-256: f31c985f422bcdbdcc11d266ab6800d46614259a61c900679702fcaf2730bcfe
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains numerous external URIs, many pointing to disposable domains, suggesting a link farm designed to redirect users to potentially harmful content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly supports this, indicating the PDF's purpose is to host a large number of links on low-reputation domains. No scripts were extracted, but the PDF structure itself is leveraged for malicious redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://smidgel.ru/uplcv?utm_term=fix+android+screens+near+me PDF link annotation
    • https://hrmconsulting.biz/upload/files/74412588426.pdfIn PDF document text
    • https://value.ae/userfiles/file/perulejiwudanuxivemonoleg.pdfIn PDF document text
    • https://eguiders.com/uploads/86501249292.pdfIn PDF document text
    • http://braintradingbcn.com/wp-content/plugins/super-forms/uploads/php/files/a9951ca217d80891e469e00f054fa46f/mowagekinarefapowi.pdfIn PDF document text
    • https://doxity.ro/ckfinder/userfiles/files/femugazije.pdfIn PDF document text
    • http://bmfjhjk.friend-match.com/upload/files/jefomexit.pdfIn PDF document text
    • http://datavincity.com/uploads/ckfinder/files/90052289439.pdfIn PDF document text
    • https://doosradashak.in/ci/userfiles/files/39037160845.pdfIn PDF document text
    • https://tessuno.com/upload/files/613e3e14f342d.pdfIn PDF document text
    • http://toroisg.com/public/images/files/datuzevomudop.pdfIn PDF document text
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613333da65ab4---zonog.pdfIn PDF document text
    • http://bangtutrang.com/upload/files/70026288673.pdfIn PDF document text
    • http://kamennykoberec.eu/editor_uploads/system/files/65087121343.pdfIn PDF document text
    • http://jobcred.com/rk/jobcred/uploads/image/file/sivogoleritizevinawu.pdfIn PDF document text
    • http://ecofincas.net/ckfinder/userfiles/files/69967574581.pdfIn PDF document text
    • https://fotoprint.lv/downloads/file/1594370362.pdfIn PDF document text
    • https://treasurehunterdetectors.com/ckfinder/userfiles/files/98757273498.pdfIn PDF document text
    • http://security-m.jp/tool/images/file/38485990241.pdfIn PDF document text
    • http://usmleworkout.com/files/file/lesexow.pdfIn PDF document text
    • http://nhasachthunam.com/upload/files/ridogovop.pdfIn PDF document text
    • http://pinxedien.net/upload/files/27011161609.pdfIn PDF document text
    • https://willes-gb.com/uploads/files/202109131322341314.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_off0000d19c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD19C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e9b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9B3 10468 bytes
SHA-256: 327287df578bb90de0aa620791836095bbaf97616fbd315c97fd91a40e794637
font_02_sfnt_off0001016a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1016A 18356 bytes
SHA-256: 3e40842be1f3ba73c7b022f5daa4972ee267ef0efcade5b2011aa95eee9eecd0

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