Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef6b36a4d0ca8ae7…

MALICIOUS

PDF

80.1 KB Created: 2021-09-06 12:03:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 525ac7638300677857d6d0ac1e208c2e SHA-1: 7efac81af048a284780b811bc91cc68799a397cb SHA-256: ef6b36a4d0ca8ae7f4730ee53998ead0319f2f1a69b30457c36523445aba6354
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs that form a link farm, pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or malware distribution scheme. The PDF structure itself does not contain readable content, but the presence of these external links is the primary indicator of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 https://smidgel.ru/uplcv?utm_term=ejercicios+de+relative+clauses+con+soluciones+pdf PDF link annotation
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/3cgpgmk13o1d5heudhf8lh99k4/xoxoxegasiwexak.pdfIn PDF document text
    • http://driver-jazda.pl/upload/file/47430487787.pdfIn PDF document text
    • https://elpmarketing.ca/wp-content/plugins/super-forms/uploads/php/files/b384cb6d808a1d2cd23d0b09f0647a2c/tafenejebutarananiwikemef.pdfIn PDF document text
    • https://www.onestopnaturalstore.ca/wp-content/plugins/super-forms/uploads/php/files/fj5gn4a9r0ac0vpl6a763kjb50/kulojavorowelinesimo.pdfIn PDF document text
    • https://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608c192e4cf01---sumejeziwipugipajo.pdfIn PDF document text
    • http://nfraccon.org/userfiles/file/rokelowire.pdfIn PDF document text
    • https://ateneoarbonaida.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085d20d77340---kolataniladozuladipujuk.pdfIn PDF document text
    • http://golden-candies.ru/webroot/files/files/71627716630.pdfIn PDF document text
    • http://cageart.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160b2a36806588---dafufuwametivaxiwi.pdfIn PDF document text
    • http://vizit-k.net/uploads/editor/files/51829906299.pdfIn PDF document text
    • https://bostoncake888.com/UserFiles/files/90517135270.pdfIn PDF document text
    • https://citytrafik.nu/images/file/86497493709.pdfIn PDF document text
    • https://samsunyapi.com/userfiles/files/bupuroferolekaxiv.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/n6oqhlbcl9uk5ppl9dqeon00t7/51719755064.pdfIn PDF document text
    • http://www.fullmooneye.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608222cc91b26---95081763471.pdfIn PDF document text
    • http://kimbuunguyen.com/uploads/userfiles/file/86027424589.pdfIn PDF document text
    • http://mp-journal.com/media/file/gexopufosurepubev.pdfIn PDF document text
    • https://ismart99.net/upload/files/18981815978.pdfIn PDF document text
    • http://jmlukanich.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/96836510228.pdfIn PDF document text
    • http://verzorgingsindex.nl/images/uploads/wajuratofetugiwavu.pdfIn PDF document text
    • http://nhactheducthammy.com/upload/files/92038274316.pdfIn PDF document text
    • https://medtek.vn/storage/file/duteku.pdfIn PDF document text
    • http://cabini.it/userfiles/files/80300491030.pdfIn PDF document text
    • http://backupcenters.com/userfiles/file/90104213090.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_off0000cf47.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF47 10892 bytes
SHA-256: de9dce3f05f0174c64feeaea3c63c11bcdf161120a9e5e89fcc4b28889bf7ba3
font_01_sfnt_off0000e890.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE890 19540 bytes
SHA-256: e8febea3f4f67110648373e3e7f8f4378afaa6063c1cde8cda64b9ace77cdae9
font_02_sfnt_off00011a49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A49 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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