Malicious PDF — malware analysis report

Static analysis result for SHA-256 5f21c4bb9ebb877f…

MALICIOUS

PDF

86.2 KB Created: 2021-07-02 07:19:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 09e4ae88fcb367316bcd5930a75d124f SHA-1: 790c977ebd79e568ccb306dec02ccc399369db56 SHA-256: 5f21c4bb9ebb877fa2ee9789da2d058e141f32ba245a3b46ecbf54a2ad2a5e8f
96 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to multiple compromised WordPress sites, which in turn host other PDF files. This suggests a tactic to manipulate search engine rankings or distribute malicious content through a chain of compromised resources. The ML classifier strongly indicated maliciousness, supporting the link farm heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 5

  • 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://ipcare.nl/wp-content/plugins/super-forms/uploads/php/files/qgr4s0j128vhcf426kbu1rrb3l/18609624661.pdf In PDF document text
    • https://vashadvokat82.ru/wp-content/plugins/super-forms/uploads/php/files/279fb254bf5becbdb56951f3e1e26a2b/91399182827.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c66b256410---xuvalun.pdfIn PDF document text
    • http://thanhlamresort.vn/wp-content/plugins/formcraft/file-upload/server/content/files/1607fda7c94ad7---9183966338.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/file/18599095416.pdfIn PDF document text
    • https://nasroglobal.com/userfiles/file/gegodakuvanifefaxerara.pdfIn PDF document text
    • http://www.training4thefuture.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160832fe35097e---86641688781.pdfIn PDF document text
    • http://mobilesamara.com/img/files/file/48272011299.pdfIn PDF document text
    • http://atlantichomeportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6d57df028b---netixoti.pdfIn PDF document text
    • https://zanhotel.ro/beficientconsultingFiles/file/bopefamejolisagaxalel.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ccf21130c4a---rixafobusadimapekudejib.pdfIn PDF document text
    • http://3duct.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094f0c2b6ca4---sadoliture.pdfIn PDF document text
    • http://appartenvue.net/appart/upload/images/fupupigo.pdfIn PDF document text
    • http://irishheritagesociety.net/clients/7/7f/7f3653e4c5d791bf76f28d2bf9929747/File/72502706341.pdfIn PDF document text
    • http://vitaminyplus.eu/files/file/76561272240.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607b807cbaf7d---tozebuzuxu.pdfIn PDF document text
    • https://olterus.com/contents//files/bopofewadukuvibetitofexu.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/945vckj6rk2eesdqhrt7rt7obd/64588046341.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606d5a3e3dd15---zulalatetig.pdfIn PDF document text
    • http://babywagen24.de/userfiles/file/felelolevisaxefiwinija.pdfIn PDF document text
    • https://rclurie.com/wp-content/plugins/super-forms/uploads/php/files/bca07c36428d3cdad619b9388aa4135b/17173123805.pdfIn PDF document text
    • http://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1606cca4724c28---vuvotog.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=shock+therapy+for+kidney+stonesPDF 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_off0000ed40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED40 10952 bytes
SHA-256: 39423e58d29fc1de0e9ba42e927bacb507344a305cd30be3964d6866dac3eb4e
font_01_sfnt_off000106a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106A0 17372 bytes
SHA-256: 4ba481552acb04e643f909e3d2205056d126907d4efb0740c3e6b9e7ee19df10
font_02_sfnt_off0001337f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1337F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1