Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8c2fbc97ca46662…

MALICIOUS

PDF

82.4 KB Created: 2021-09-07 04:01:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: f6863fd4c2127411278c6d8c1850e422 SHA-1: d91e9e25cff88877af1c645ef0b73d9936fdefb5 SHA-256: a8c2fbc97ca46662fc06ab14aaf83fa54fa629bbdc89a57c35b240a017300931
156 Risk Score

Malware Insights

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

The ML classifier and ClamAV detection strongly indicate this PDF is malicious. It contains numerous links pointing to compromised CMS uploads and disposable hosting, suggesting it's part of a link farm designed to redirect users to malicious sites. The PDF's structure and the presence of multiple external URIs, some hosted on compromised WordPress sites, support this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://contactfm.be/userfiles/files/10506203418.pdf In PDF document text
    • https://www.nosolodespedidas.es/wp-content/plugins/formcraft/file-upload/server/content/files/160bdb73b54a50---67016199747.pdfIn PDF document text
    • https://www.nordatec.com/wp-content/plugins/super-forms/uploads/php/files/rbf3bt6vfmk86f5qduojasl1fj/juwojixixamuxezodub.pdfIn PDF document text
    • http://pooq-design.com/app/webroot/fckfiles/file/nutokabo.pdfIn PDF document text
    • http://vdadanang.vn/app/webroot/assets/files/89882547753.pdfIn PDF document text
    • http://modellszerviz.hu/userfiles/file/15946157173.pdfIn PDF document text
    • http://bharatdarshan.net/rgroup/ckfinder/userfiles/files/82380630453.pdfIn PDF document text
    • http://keralastatetailorsassociation.com/userfiles/file/zuzerosol.pdfIn PDF document text
    • http://murasakijr.com/uploads/files/86538827804.pdfIn PDF document text
    • https://www.lenoir-elec.com/wp-content/plugins/super-forms/uploads/php/files/542m0mqoniiir8dap099o7khtj/89994905894.pdfIn PDF document text
    • https://clinicscrm.com/img/files/kumuzudajumadolopuses.pdfIn PDF document text
    • https://www.ideaklinik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160731d3748050---sidopepo.pdfIn PDF document text
    • https://aksusu.com/upload/files/xusuja.pdfIn PDF document text
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/160c9076203af2---dakenajefinadupam.pdfIn PDF document text
    • https://www.autodepotperformancegroup.ca/wp-content/plugins/super-forms/uploads/php/files/pmo9no089g78nq1l2trltt7t4c/53008121069.pdfIn PDF document text
    • https://webmodeli.com/wp-content/plugins/formcraft/file-upload/server/content/files/160dde7fee6adc---29227982537.pdfIn PDF document text
    • http://changjiujz.com/uploads/files/202109070459533594.pdfIn PDF document text
    • http://studioschicchi.eu/userfiles/files/73828587692.pdfIn PDF document text
    • https://www.ideaklinikkadikoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c6863f1b88f---86812703881.pdfIn PDF document text
    • http://brianhaymore.com/images/e/file/85418756261.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=canada+hypertension+guidelines+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_off0000d8ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8ED 11020 bytes
SHA-256: c87f391a08fcaea4092707d84369adea597407a0f45c94eb103fa031eb3ad049
font_01_sfnt_off0000f24d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF24D 18972 bytes
SHA-256: 7b22f7a4411af9437f6c86bcc3470ec0addb71da6ac4847ac42477f251683bea
font_02_sfnt_off000123f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123F0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1