Malicious PDF — malware analysis report

Static analysis result for SHA-256 81dee9f97213a855…

MALICIOUS

PDF

122.7 KB Created: 2021-07-08 12:15:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 2fd1fc2d518b04ed306f9133427960da SHA-1: 4ff5b0ff779dc7f5b7cd257041079d2c100686e9 SHA-256: 81dee9f97213a855e027455ee8b092e2aaf1379bbf55169073ef55f3e299f389
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a link farm pointing to multiple compromised WordPress sites, as indicated by the 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. While no scripts were explicitly extracted, the nature of the links suggests a redirection mechanism, potentially leveraging embedded JavaScript or other PDF features to initiate the attack chain.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9938

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://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d2e7b890ef7---zadufidurovulo.pdf In PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/jewubukelepupuwimavalov.pdfIn PDF document text
    • http://profisystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160c53b4170148---3851231068.pdfIn PDF document text
    • https://carpanea.it/wp-content/plugins/super-forms/uploads/php/files/f63cbd60c4aa692ec387cded82b88d91/penulujavoges.pdfIn PDF document text
    • https://microfocus-realize2020mea.com/wp-content/plugins/super-forms/uploads/php/files/8a5c8fbd0d1b83d4140b0b91df40b6cf/bipuvufaperapaf.pdfIn PDF document text
    • https://chamsocmuihong.com/wp-content/plugins/super-forms/uploads/php/files/ulgpvs1u3ohsm6fh4qoaljg2oa/4607159779.pdfIn PDF document text
    • https://yournew.site/wp-content/plugins/super-forms/uploads/php/files/r3kgr7mrincgmorh3erhi8d687/63912643976.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16076dc0b67d46---nitatolox.pdfIn PDF document text
    • http://xn--b1ahhafccpgkb2bxo.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/61825d9ce37eb1391159e4b5042ba627/bovabozubog.pdfIn PDF document text
    • https://swotin.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c6cd9728d4---86435940702.pdfIn PDF document text
    • http://sazjah.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608098a948f9f---tetikezewibidez.pdfIn PDF document text
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/f62b98aa134ea3f103718a0767861ced/55731191910.pdfIn PDF document text
    • http://moderncarrent.com/user_img/files/4955781778.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/8nt3aeajajfsh3g02c30dsm214/97873776770.pdfIn PDF document text
    • http://pansophers.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae730f7517c---17212770555.pdfIn PDF document text
    • http://myafmc.com/clients/a/a5/a51d49d85de18111a3d718c63a5e5081/File/latavidosozulavitok.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/89182958329.pdfIn PDF document text
    • https://thesaddlebank.com/wp-content/plugins/super-forms/uploads/php/files/e4uff504tde89n978cui1tl9jo/48644264681.pdfIn PDF document text
    • https://afriqueitnews.com/wp-content/plugins/super-forms/uploads/php/files/64b9c440bbfde0b279bff4a9379d4845/47363494434.pdfIn PDF document text
    • https://f-kcc.jp/user_data/userfiles/files/varuropego.pdfIn PDF document text
    • http://carrollcountylawyers.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/lidofabala.pdfIn PDF document text
    • http://optimus.org.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608ac8cb10fc2---jodixela.pdfIn PDF document text
    • http://ibtaker.ps/userfiles/file/novogizunukuka.pdfIn PDF document text
    • https://www.rowtheerne.com/wp-content/plugins/super-forms/uploads/php/files/8b1d34c5151f45497c1d4d051694056d/ratomisirasesebobovuditer.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/4k41e2i41p7j5sh5jm5tv889mb/82419629363.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=griffiths+solutions+electrodynamics+3rd+editionPDF 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_off00016cc5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16CC5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000184d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x184D7 22812 bytes
SHA-256: 6f2f438cda67df8781e4219fb5c2dce8d26a269c3c7911c514bebdf5c778bf62
font_02_sfnt_off0001c30c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1C30C 11168 bytes
SHA-256: 49ff8bc15630abca04f95a4d3ce71a8335c05b8ba040e1796b76a2f1516d2d4a