Malicious PDF — malware analysis report

Static analysis result for SHA-256 81ab04541c8824c0…

MALICIOUS

PDF

89.9 KB Created: 2021-07-17 10:59:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 103b8da9fbf443eff2b485936aa78ee3 SHA-1: fa2895f107d83bd1e4db13ac5a48909f5538da0f SHA-256: 81ab04541c8824c0bf76b122b5fae5a2c5e6a09ed94cb20ac83db70e1a81dc1e
156 Risk Score

Malware Insights

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

The PDF contains a link farm directing to multiple distinct hosts, many of which appear to be compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, suggesting the PDF is designed to leverage these compromised sites for hosting or redirecting malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9922

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 http://tuzvedo.hu/elemek/file/fepakeludedivefot.pdf In PDF document text
    • http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d35cb8a3940---19757498675.pdfIn PDF document text
    • https://chamsocmuihong.com/wp-content/plugins/super-forms/uploads/php/files/cf90nbfjgoama2kbvnnknumodj/rivorixivelapifi.pdfIn PDF document text
    • https://kalatranslation.co.uk/wp-content/plugins/super-forms/uploads/php/files/t215l240r011qmugfnqn0b4ji4/sipegeluzug.pdfIn PDF document text
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607bfc61df280---zuromij.pdfIn PDF document text
    • http://vekosgroup.ru/userfiles/file/98218272771.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/160bc39439f2ad---ferolitoratozegufivevobo.pdfIn PDF document text
    • http://cathyknightwaite.com/ckfinder/userfiles/files/kuwimi.pdfIn PDF document text
    • http://nano-vip.com/ckfinder/userfiles/files/rodewakuzeke.pdfIn PDF document text
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/mi001q1cn84crl23v5h056aipe/zunisifuvav.pdfIn PDF document text
    • https://lexcochoralsoc.org/demo/lccs/beta/userfiles/files/ronusepadasifagokesolavej.pdfIn PDF document text
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160efd9b381680---24931742813.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607aa8cdb224c---19804283593.pdfIn PDF document text
    • https://comodee.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c3c5078c137---nitavebalaki.pdfIn PDF document text
    • https://nslogisticservice.com/userfiles/files/88284321128.pdfIn PDF document text
    • http://uni-farm.pl/ckfinder/userfiles/files/muvuxibo.pdfIn PDF document text
    • https://bd-sokolovska.eu/userfiles/file/54488139198.pdfIn PDF document text
    • http://moriefrusca.com/userfiles/files/59427327903.pdfIn PDF document text
    • http://nuyewpilot.academy/wp-content/plugins/super-forms/uploads/php/files/abcc9b015ee0b65f5630dc2df4b8a1cd/tasojenivununezekuno.pdfIn PDF document text
    • https://tl-systems.hu/files/files/26257769296.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/160ecaaf8d2588---puvepoz.pdfIn PDF document text
    • http://www.iycadana.org/wp-content/plugins/super-forms/uploads/php/files/fsp1s6mougqi9bkufk70enkho2/4211191688.pdfIn PDF document text
    • https://zahnersatz.pl/userfiles/files/79513626790.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210506232942803256045.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607611959e3f9---toporadakumidufef.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=detection+and+estimation+theory+lecture+notesPDF 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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ed5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED5E 2628 bytes
SHA-256: d7c61c1395714de4bdef1e2053911843eb9e9db71fb1de60469cc8de4735bfc1
font_01_sfnt_off0000f85c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF85C 17492 bytes
SHA-256: 195f283b42d98510c0d30cdbd9e750fdf329fb976aacc0e962bf92419bde329a
font_02_sfnt_off00012693.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12693 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00013eaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13EAA 10852 bytes
SHA-256: f4ead736097a50d148fbfb2a9978aff3ce5af3cb0db99c367dbb2c7a1d909b6f

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