Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8c34d1255c658d6…

MALICIOUS

PDF

86.6 KB Created: 2021-09-02 09:07:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 81d64b511f86675dd17e57dab7f75def SHA-1: 92c752e7833d1ac4ba0bea96bc7d6147132dc50b SHA-256: c8c34d1255c658d654eb4bae99a5c687914928f4f2219c9e7d06f8af78c6d748
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The ML classifier and ClamAV detection strongly indicate malicious intent. The PDF contains numerous embedded URLs, many pointing to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, indicating a tactic to obscure the true destination of the links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://chcial.ru/uplcv?utm_term=check+mark+symbol+in+outlook+email PDF link annotation
    • https://www.ideaklinikbursa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a5808ddb61---5379332952.pdfIn PDF document text
    • https://parklanehotel.asia/userfiles/file/77613260488.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/talozito.pdfIn PDF document text
    • http://villa-carlshorst.de/sites/default/files/file/vugiwelogimunezoza.pdfIn PDF document text
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130240d20188---laferapezukanipa.pdfIn PDF document text
    • http://host.keraladreamhomes.com/~viswabrahmathach/admin/fckeditor/editor/filemanager/connectors/php/userfiles/file/batijusomuduxodit.pdfIn PDF document text
    • https://iwanbim.iwan.co/userfiles/files/25605769917.pdfIn PDF document text
    • http://afgventuregroup.com/cfiles/file/43830312860.pdfIn PDF document text
    • https://reifenscho.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607b607377629---47881697151.pdfIn PDF document text
    • https://gdr.co.il/wp-content/plugins/super-forms/uploads/php/files/a676b8641fd17d88a3df93a2fe87a585/1410572656.pdfIn PDF document text
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160981f1b195a1---21148875440.pdfIn PDF document text
    • http://salkim.com/userfiles/file/28130078748.pdfIn PDF document text
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/734c1d9455ae6d9030b8b1231a20ee5f/dodetidop.pdfIn PDF document text
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16129dccda8695---xajajerewaverasewafuma.pdfIn PDF document text
    • http://mountmedpharmacy.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1609b1a0db68c3---fomenupuxejiful.pdfIn PDF document text
    • https://spazmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610bb14946f40---83906003820.pdfIn PDF document text
    • https://aprilboya.com/userfiles/file/bepupunugoder.pdfIn PDF document text
    • http://dxczx.com/ckfinder/userfiles/files/20210602_074359.pdfIn PDF document text
    • http://cyuanmei.com/userfiles/file/96679593733.pdfIn PDF document text
    • http://www.airportlimofortlauderdale.net/wp-content/plugins/formcraft/file-upload/server/content/files/16107133e143a4---25371694169.pdfIn PDF document text
    • http://www.contectrade.hu/fckfiles/file/58400765946.pdfIn PDF document text
    • http://brandweeramsterdamamstellanden.nl/userfiles/file/47955172075.pdfIn PDF document text
    • http://grupogmec.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3b33d9a2d1---tiporasurelopumagokiri.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_off0000e897.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE897 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000100ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100AE 10972 bytes
SHA-256: 187f5b24391a5dcc5d9b668a8f776d2655e6ab2600fcc689d9750c05fdd26814
font_02_sfnt_off000119fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119FE 19356 bytes
SHA-256: 77cce9de101c8d6387c48359773f2d69def5d0d931ccc89d525f2f5a79bc5783

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