Malicious PDF — malware analysis report

Static analysis result for SHA-256 6152aa3fb94f6a89…

MALICIOUS

PDF

79.0 KB Created: 2021-07-07 01:01:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: a5413e4f02cf96c483e925b32aa38772 SHA-1: 157b07436daf2255d07cac3241c0e0db4f5d5f28 SHA-256: 6152aa3fb94f6a89f2dd99f281eae961216adddde5e4cbfc5ed438b646aed4e1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with numerous URLs pointing to compromised WordPress sites and other domains, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, but the presence of external URIs and the overall structure strongly suggest it is designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://cructi.ru/uplcv?utm_term=how+to+read+and+write+decimals PDF link annotation
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/4322b4aee970007460baae2e6acd1fd3/dapaxitejexefunolakav.pdfIn PDF document text
    • http://ubestsports.com/imager/files/20210627093709.pdfIn PDF document text
    • http://chanakyaaerospacedefence.com/userfiles/file/25244204755.pdfIn PDF document text
    • https://aradovan.com/userfiles/file/jofakozudalumebu.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/bf84bb87a90a74258e52fbeb61d3c85d/giruxagofixe.pdfIn PDF document text
    • https://advancedbusiness.co/wp-content/plugins/super-forms/uploads/php/files/dc17e287bf3dcbc00ab2b888e3114373/52662363067.pdfIn PDF document text
    • https://beautyreviveshop.com/newerac2c/userfiles/file/28810814367.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/c9bf2962709209d49cabf36ca44a6c4b/poxiwuwakimiluja.pdfIn PDF document text
    • https://dermo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f88685c55f---32612454391.pdfIn PDF document text
    • https://www.clubmanizales.com.co/wp-content/plugins/formcraft/file-upload/server/content/files/160c9455e7f629---tununinizagafawato.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b0841db8220---25777834534.pdfIn PDF document text
    • http://w-f-l.de/user_img/file/jugulonokaf.pdfIn PDF document text
    • http://www.cafeinca.com/img/public/contenido/file/wunuzefixetimijeda.pdfIn PDF document text
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/b7b83f884272c3cd0afbc1c245ffb418/monuzewatala.pdfIn PDF document text
    • http://say-international.eu/userfiles/file/fesawegevozemesorodilagux.pdfIn PDF document text
    • http://nebo52.ru/uploads/files/mopado.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/160ce10a647f4f---50175601473.pdfIn PDF document text
    • https://0900107678.com/upload/file/bumok.pdfIn PDF document text
    • http://friluftsgruppen.se/wp-content/plugins/formcraft/file-upload/server/content/files/160b977c4d4939---21119138927.pdfIn PDF document text
    • https://studiogreenwich.ru/wp-content/plugins/super-forms/uploads/php/files/1626332739dccf8d4b18e7d76152a2e8/livafozudixawox.pdfIn PDF document text
    • http://yangs-ns.com/ckfinder/userfiles/files/20210528014359.pdfIn PDF document text
    • https://energiadirect.pl/application/resources/ckfinder/userfiles/files/50258916456.pdfIn PDF document text
    • http://klefmarken.se/upload/file/37034144363.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c009a21d1fa---74041773018.pdfIn PDF document text
    • 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_off0000cfe7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFE7 17616 bytes
SHA-256: 3453e6d03a4083697a1f82fd0464721966add494c0363084cb76fc51a6d8e7c8
font_01_sfnt_off0000fe75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE75 10608 bytes
SHA-256: 8d75ad9b19fff6d2e47885b0b971504b8990bab9641ddf844e8ed4ad566f4811
font_02_sfnt_off000116af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116AF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1