Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb87db23f211e1bf…

MALICIOUS

PDF

76.5 KB Created: 2021-09-04 09:46:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 79049318b703cc07868f6e99b40e8565 SHA-1: 5cc04f49166af598dbb457faeebd3d38d4441f22 SHA-256: cb87db23f211e1bf6f357a4595a3956ce0ae871352b2c6973cd42dc1a0ca4515
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to obscure the ultimate destination. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the heuristic firings clearly point to a malicious link farm attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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 http://bertrandetgastineaudesigners.com/userfiles/file/ziroger.pdf In PDF document text
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608068d784360---pazutiwowomew.pdfIn PDF document text
    • http://amfmeg.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606f5210f08db---19568070321.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160e72457e43e8---44036636292.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9f9fcc9116---65661464900.pdfIn PDF document text
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/1607a6afc41329---bibapuvun.pdfIn PDF document text
    • https://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/0e8aaa06c8d0d985dde6cf6e07477994/86867253991.pdfIn PDF document text
    • http://abwcolley.com/uploads/files/79314366560.pdfIn PDF document text
    • http://gingerwooddesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5b5fe714b5---kamelujuritit.pdfIn PDF document text
    • https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/3dc1fe01f938372b23b4121d44d39e52/koredatujematulizafuzivo.pdfIn PDF document text
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096da8557da4---poxilijuwof.pdfIn PDF document text
    • http://secretinvitation.net/images/files/kutokonome.pdfIn PDF document text
    • http://freemansphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d1a51c595b---81736665172.pdfIn PDF document text
    • https://www.tyrtaios.gr/ckfinder/userfiles/files/61527119738.pdfIn PDF document text
    • http://nationshield.ae/userfiles/files/55266415884.pdfIn PDF document text
    • http://ampletrekking.com/userfiles/file/tivajutibupav.pdfIn PDF document text
    • http://goodmix-psc.com/userfiles/files/22170696597.pdfIn PDF document text
    • https://www.mppoa.cloudlinesystems.com/assets/ckfinder/userfiles/files/wumemadezomo.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607f35adcd533---kufurixekuxijekoki.pdfIn PDF document text
    • https://yensaovinastar.com/media/files/41521041803.pdfIn PDF document text
    • https://mystruggle.uk/indigo/ckfinder/userfiles/files/55448016518.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1612af4d947acf---bexugexejo.pdfIn PDF document text
    • https://mavismanagement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089d7781eb2d---5327581476.pdfIn PDF document text
    • https://www.jnvhardoi.org/ckfinder/userfiles/files/16567040280.pdfIn PDF document text
    • https://adbadog.com/wp-content/plugins/super-forms/uploads/php/files/f0bcb111489c9c841f9672b5584982c3/fokajivaligex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=immunohistochemistry+methods+pdfPDF link annotation
    • https://tes-sys.com/uploads/ckfinder/files/20210713/16261258968047.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_off0000c76b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC76B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000df7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF7D 16944 bytes
SHA-256: b028172b51a15a3920d61f98b6d3ef2278f50801a30d6ad8c6ca930d31f1a567
font_02_sfnt_off00010afe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AFE 10844 bytes
SHA-256: f865763760e324f2c014bc88f7061339b6c06b6a1e95bda4ba70eef022b56d06

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