Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5a24118e5625a14…

MALICIOUS

PDF

71.4 KB Created: 2021-10-02 09:47:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: b1e28dbcc674dbfb0b9bc91cb92306ea SHA-1: 34e42d6f8113b2432df2dfbe526ff771955281f0 SHA-256: b5a24118e5625a140fc92ae8b2dcb60b239a1943d68dfc77eb311691f1e8efd1
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as containing a link farm and was detected as malicious by ClamAV and an ML classifier. The heuristics indicate the document is designed to host numerous links, many pointing to potentially compromised or disposable hosting, suggesting an attempt to direct users to malicious sites. No scripts were extracted, and the document body was unreadable binary data, but the presence of multiple external URIs and the link farm heuristic strongly suggest a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16155fb5ce8c1a---zurebutegisewep.pdf In PDF document text
    • https://tekstilkent.formenemlak.com/upload/ckfinder/files/56712267741.pdfIn PDF document text
    • https://icon-studios.com/userfiles/file/17361147319.pdfIn PDF document text
    • https://tasivn.com/upload/ck/files/gixoximoni.pdfIn PDF document text
    • http://24horasnoar.com.br/ckfinder/userfiles/files/zivun.pdfIn PDF document text
    • http://lepixz.com/userfiles/file/80519177313.pdfIn PDF document text
    • http://www.ochoadentalcare.com/tacgestorcontenidos_ochoa/documentos/file/In PDF document text
    • http://nataliashishkina.com/userfiles/file/18490052385.pdfIn PDF document text
    • http://kargiskola.ge/myadmin/ckeditor/ckfinder/userfiles/files/parefotejuji.pdfIn PDF document text
    • http://jtour.vn/userfiles/file/33554122204.pdfIn PDF document text
    • http://www.anglometais.com.br/adm/Editor/ckfinder/userfiles/files/67501030162.pdfIn PDF document text
    • http://np-laser.com/upload_fck/file/2021-9-25/20210925040924774964.pdfIn PDF document text
    • https://masterpieces-mallorca.com/wp-content/plugins/super-forms/uploads/php/files/cfbb9a33357d948b6cf12a01f06e47bf/vumelofugamisebokogure.pdfIn PDF document text
    • http://baikalspring.ru/ckfinder/userfiles/files/38670419192.pdfIn PDF document text
    • http://www.bestlifepolicy.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161493c7ce1f12---69891454502.pdfIn PDF document text
    • https://hagakure.by/upload/editor/files/ridedoradinumenude.pdfIn PDF document text
    • http://design-klasse.de/ckfinder/userfiles/files/pudijemudet.pdfIn PDF document text
    • http://roocenter.ru/upload/file/53864340299.pdfIn PDF document text
    • http://mixmarketing.vn/upload/fck/file/34777450653.pdfIn PDF document text
    • http://lirealestatelitigator.com/wp-content/plugins/super-forms/uploads/php/files/8ed17ed0eafb3767a39168c26514b6a0/93149486426.pdfIn PDF document text
    • https://matratva.in/userfiles/file/jabejewafuxufutajiluga.pdfIn PDF document text
    • http://fabiocaronearchitetto.com/userfiles/files/juluwupegunotuferir.pdfIn PDF document text
    • https://napraforgohotel.hu/upload/file/38843885924.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=six+rational+number+between+3+and+4PDF 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_off0000b161.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB161 10992 bytes
SHA-256: 08e493599acab231f4ee3947d700eea7024bf525517ff6c8d65a999d23b40fb2
font_01_sfnt_off0000cb01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB01 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e313.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE313 16744 bytes
SHA-256: 5636af8145aabc8b6b0fd887157968223bb5618a51a0bd53bf7576a4e3ccc105