Malicious PDF — malware analysis report

Static analysis result for SHA-256 c16fe8eb5665188c…

MALICIOUS

PDF

84.0 KB Created: 2021-09-04 08:47:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: f73bd37346ef326ad4ac1e806e23adf4 SHA-1: d64fdc27c8cd8fa63572ecbbde154df81cb35761 SHA-256: c16fe8eb5665188ca2a03feb80814aa947c33529bdd53403f388caa14e6957da
96 Risk Score

Malware Insights

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

The PDF contains a link farm, directing users to multiple URLs hosted on compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic confirms the nature of the links. While no scripts were extracted, the structure and heuristics point to a phishing or redirection attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 http://blog.crowdly.com/wp-content/plugins/formcraft/file-upload/server/content/files/160820d4cb7174---95023716561.pdf In PDF document text
    • https://www.endthestigmacounselling.com/wp-content/plugins/super-forms/uploads/php/files/5edihcpueuj0g8kgq3vflvgh2v/16172512737.pdfIn PDF document text
    • https://jamisonfurnace.ca/userfiles/files/lobiwawovovaxupeberoletat.pdfIn PDF document text
    • http://korean-school.hu/hangul/userfiles/file/bugejipezetadusewupi.pdfIn PDF document text
    • http://halongbaycruises.org/upload/files/vitedezerabunizudapan.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/bjvuhsvkf6038jf708smr17jg1/kusowifoxono.pdfIn PDF document text
    • https://tcufroghouses.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c071b388f42---giribivofirovusixes.pdfIn PDF document text
    • https://airflow-skateboards.com/userfiles/files/23528765323.pdfIn PDF document text
    • https://rhdplumbing.com/wp-content/plugins/super-forms/uploads/php/files/8610941ce04fe676edaf15aaf546bf81/fowumeridivix.pdfIn PDF document text
    • http://nadiadsa.org/userfiles/file/tuxewadejujezewokakuzewe.pdfIn PDF document text
    • http://auto-spec.ca/fck/file/70754441283.pdfIn PDF document text
    • https://refour.eu/wp-content/plugins/super-forms/uploads/php/files/62a90b0d2292ab63083913c73b6d7afa/botejaderibut.pdfIn PDF document text
    • https://kolodezrus.ru/wp-content/plugins/super-forms/uploads/php/files/5e2fc810ffdbe535ac582feb2be05328/91766379977.pdfIn PDF document text
    • http://stellar.ru/ckfinder/userfiles/files/87781461664.pdfIn PDF document text
    • http://arcadia1973reunion.com/clients/3/33/33cb7023d77084166ed027ca16b579b7/File/lifix.pdfIn PDF document text
    • https://viajespereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610bc79470549---41161438918.pdfIn PDF document text
    • http://vtdsbinhthuan.vn/public/uploads/userfiles/file/bopogifenemodikowe.pdfIn PDF document text
    • http://trineckevzdelavani.cz/webpagebuilder/ckfinder/userfiles/files/fijusuwigogemutuvavur.pdfIn PDF document text
    • https://readxyz.org/wp-content/plugins/super-forms/uploads/php/files/42e3321c1288f6a934421987790c5ecd/mefenuduvulagojulajuseda.pdfIn PDF document text
    • https://www.idromeccanicasrl.com/idromeccanicasrl.com/wp-content/plugins/super-forms/uploads/php/files/a11fb41164d78a54ffda9843703b2adc/70142456927.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=pastorala+americana+pdfPDF 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_off0000e01d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE01D 10780 bytes
SHA-256: 88a38655e9cff0d059d82ab13392ca18d6eb41afe5bec03439deae0f7925a9c6
font_01_sfnt_off0000f8eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8EB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000110fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110FD 19364 bytes
SHA-256: 7e59ff9d324892bda6433a07be8200ff61f5b6d9deb48dd5835ab72dc99dd200