Malicious PDF — malware analysis report

Static analysis result for SHA-256 85a20db5a187f4cb…

MALICIOUS

PDF

78.1 KB Created: 2021-08-26 13:16:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: ca8b0b5e1e444e498dd2a8f7a41da56d SHA-1: 89e2f0fa3e4436a4eabdb5ca0056e8643079dc03 SHA-256: 85a20db5a187f4cb8504fec5fc02048aba02db862ec51b30ac8457563f3fcd48
156 Risk Score

Malware Insights

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

The PDF contains a link farm with multiple URLs pointing to various domains, many of which are hosted on compromised CMS upload storage or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to redirect users to phishing or malware distribution sites. The presence of numerous external URIs and the link farm structure suggest an attempt to obscure the final destination and potentially exploit vulnerabilities in PDF viewers.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://sunrui-ti.com/d/files/bomunigotowikivirefapes.pdf In PDF document text
    • http://af.ssla.ru/images/fornews/files/54729495776.pdfIn PDF document text
    • http://redondoclassicburger.com/uploads/files/gigolizolaga.pdfIn PDF document text
    • https://toscanafantastica.com/userfiles/file/birojupijusoko.pdfIn PDF document text
    • http://cec-intl.ru/app/webroot/files/file/jovegin.pdfIn PDF document text
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/5e65ddeb6713b78bbe71bc3426fe06b5/76881155882.pdfIn PDF document text
    • http://hamandeggsclub.com/clients/e/ee/ee862789ee8b59d3f3d22261ccc35c80/File/fexazibazedizivo.pdfIn PDF document text
    • https://fitnessrev.net/wp-content/plugins/super-forms/uploads/php/files/c21bg6esib07gdbqq0208cp3jq/51786073762.pdfIn PDF document text
    • http://joelcsimonesq.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/65772272621.pdfIn PDF document text
    • https://www.geosuiteonline.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609e9fc6d707f---puwumapesatejivaguzagofex.pdfIn PDF document text
    • http://clingac.com/d/files/40392731286.pdfIn PDF document text
    • http://diagonal.org.ar/wp-content/plugins/formcraft/file-upload/server/content/files/1606f32df55093---likegajavipizuvuk.pdfIn PDF document text
    • http://doks-films.com/pcms/content/file/26759980716.pdfIn PDF document text
    • http://www.sunarpazarlama.com/wp-content/plugins/super-forms/uploads/php/files/debtq1r3qtsglugeucu8lfieh6/56360071810.pdfIn PDF document text
    • https://www.birdandwildlifeteam.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf4b13480bc---69240715492.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/161274244b1c3e---besoxedipepisokuzan.pdfIn PDF document text
    • https://www.web2business.pt/wp-content/plugins/formcraft/file-upload/server/content/files/160b18ae497059---totokud.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=types+of+system+analysis+and+designPDF 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_off0000d020.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD020 16456 bytes
SHA-256: 3f3ef39b33a4e4c4d1032831dd01a0155b05f33a70feb303642f6e0515930581
font_01_sfnt_off0000fac1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAC1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000112d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112D8 10816 bytes
SHA-256: 9c6f763a61edecbace6f5f8e5eac45b15081f0277556317fcd62c12df4015399