Malicious PDF — malware analysis report

Static analysis result for SHA-256 51a08859d03d2b1c…

MALICIOUS

PDF

92.8 KB Created: 2021-07-21 09:50:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: c763b08f4009230eb841cbed7916461e SHA-1: 437c2bf59a8986ee3a38bdddbb91d72e8b215215 SHA-256: 51a08859d03d2b1c438b462afe62431f40b4fc5398e60a8274f1cdca5bef83b5
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many hosted on compromised or disposable domains, indicating a link farm designed to redirect users. Heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' strongly suggest this malicious intent. The ML classifier and ClamAV detection further confirm its malicious nature, likely serving as a lure for phishing or malware delivery.

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://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/5ddfd4a26cf075a3ca3809aae57324b6/sosowibupebowikiwotera.pdf In PDF document text
    • http://valeneighbors.com/userimages/zojolozabafuxuv.pdfIn PDF document text
    • https://gmonlinestore.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d285d424c7---54612001201.pdfIn PDF document text
    • https://cspdental.com/wp-content/plugins/super-forms/uploads/php/files/78a3ff895716e650232807bdd098acd6/52369025364.pdfIn PDF document text
    • http://samuiluxurytravel.com/Uploads/file/taxasanef.pdfIn PDF document text
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b6184f83ab3---pekiborixunekexobob.pdfIn PDF document text
    • http://www.annaleehuber.com/content_files/file/kuwekovivuz.pdfIn PDF document text
    • http://blbr365.com/userfiles/file/1626673313.pdfIn PDF document text
    • https://www.brunosistemi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160777b10b06c2---pezinozisuva.pdfIn PDF document text
    • http://brezov-gaj.si/uporabnik/file/fukudoto.pdfIn PDF document text
    • http://savvyais.com/userfiles/file/tokegizuxonuviju.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160c1e05d7f4b1---domegetepor.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160e960b2559aa---14491764982.pdfIn PDF document text
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/3fe23aee6a2d50e28f2f75ee70b97a4a/40155595157.pdfIn PDF document text
    • https://forumhotel.by/wp-content/plugins/super-forms/uploads/php/files/ub8aftq1hreg2qc5vtqmbbtlt3/58051319642.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0794eb9480---telatavaruxubej.pdfIn PDF document text
    • http://debsluxe.com/clients/1/17/174397649ed9f07baa8f9d9f48c72a4d/File/1008984899.pdfIn PDF document text
    • http://cobbpaynefamilyreunion.com/clients/862770/File/32312480913.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160c4281d88c29---ruxad.pdfIn PDF document text
    • http://iideree.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b21312c889f---nobafijanimowuguxexegufis.pdfIn PDF document text
    • https://nikosdimos.gr/userfiles/file/61814628114.pdfIn PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094d6e584c5e---59582077231.pdfIn PDF document text
    • http://hattrick-sports.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e4a6fcd646f---beludelupubope.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7e2662b76f---56019740468.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=chicken+pecking+own+feathersPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001047a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1047A 17636 bytes
SHA-256: b418cead6a8822c343910c92ac3d3d994a2de0610959a19d6837af2bd3169bc7
font_01_sfnt_off000132ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x132CE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014ae5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14AE5 10924 bytes
SHA-256: a89e81cfbe9b08e04e678061782bb88ef510ecfc52f737dc8c218b8a0d9828c0

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