Malicious PDF — malware analysis report

Static analysis result for SHA-256 c839cd5b89d6173a…

MALICIOUS

PDF

92.4 KB Created: 2021-07-07 21:51:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 685a06fbc4876ff053d66ec33b074265 SHA-1: 43562bded4e5864b775cab6e0e98d96b59f3bdac SHA-256: c839cd5b89d6173a7a4f4146a4e37b2a85dab2b665af495d68dc26be24ea4e69
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, likely to redirect users to malicious content. The presence of external URIs and the link farm structure suggest an attempt to lure users to external sites, potentially for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

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://knurussian.kr/DATA/upload/files/202107061816418401.pdf In PDF document text
    • https://aldurra.ly/images-editeur/img/file/jajawob.pdfIn PDF document text
    • http://saharun.org/uploads/ckfinder/userfiles/files/42704676774.pdfIn PDF document text
    • https://ifacemount.com/wp-content/plugins/super-forms/uploads/php/files/au8bo5k82ehnkuiruabuvaiolj/99029080310.pdfIn PDF document text
    • https://www.kiteschule-eckernfoerde.de/wp-content/plugins/formcraft/file-upload/server/content/files/160d9d674bd298---65458968358.pdfIn PDF document text
    • https://alamansyria.com/userfiles/file/91927854560.pdfIn PDF document text
    • http://17njl.com/userfiles/files/95399913586.pdfIn PDF document text
    • http://seoulgreeter.com/userData/board/file/nizojunuvopufuvipi.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/2ae7edede214173f9f7fb55fd31ba521/muvurowifomenedujefowodo.pdfIn PDF document text
    • http://coss-wynn-reunion.com/clients/d/db/dbe3622004495b304d8703879a486b7d/File/20687838445.pdfIn PDF document text
    • http://plenaadoracao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b84dafe247f---76698988843.pdfIn PDF document text
    • https://accuratesearch.com/userfiles/file/ziraropemu.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/160be27bb67467---85211340310.pdfIn PDF document text
    • https://solidpractise.com/files/userfiles/file/rulareguxunazavilunosi.pdfIn PDF document text
    • https://fallsplat.se/file/42385214321.pdfIn PDF document text
    • https://californiaoptionsrealestate.com/wp-content/plugins/super-forms/uploads/php/files/eeed15f859bd0b964e86880417d711b7/44005698193.pdfIn PDF document text
    • http://dhf-china.com/d/files/67523071295.pdfIn PDF document text
    • http://szwygs.com/upload/55812488840.pdfIn PDF document text
    • https://seeandhearbetter.ie/img/shop//contents/ludaxiri.pdfIn PDF document text
    • https://medok18.ru/wp-content/plugins/super-forms/uploads/php/files/bbea7e8596869ab40b3e550636741a57/91378032729.pdfIn PDF document text
    • http://dyglas.com/userData/board/file/83963644547.pdfIn PDF document text
    • http://hkt-optics.com/hkt/images/userfiles/file/65148368101.pdfIn PDF document text
    • https://www.democratum.com/wp-content/plugins/super-forms/uploads/php/files/f25414b8c4b86f73180bb127168afddb/fivoviruginaketap.pdfIn PDF document text
    • http://hitecds.com/userfiles/file/jivodaridojuverin.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=this+is+a+true+lovePDF 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_off000108a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108A3 16724 bytes
SHA-256: 25d9980a971076c6e74dfa31c44a834ebd4f2630558df477a8248b3b0dc68d14
font_01_sfnt_off000133c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x133C8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014bdf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14BDF 10232 bytes
SHA-256: 2aa72a149899eb7a229e0129b395a9ab22ec36e596dcfd5c65963477dd4e6156

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