Malicious PDF — malware analysis report

Static analysis result for SHA-256 a91c16a5d3d3c51e…

MALICIOUS

PDF

73.1 KB Created: 2021-09-06 04:37:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 247342c94fba97b8e22493bb03013b81 SHA-1: 59eb2641563537d3fd1df91ea57aa4ab8d0e561a SHA-256: a91c16a5d3d3c51e8d5e4ca8be925777f52767046b83aefe1614eb7c5040c6b2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many URLs pointing to potentially compromised websites or disposable hosting. The document body is unreadable, but the presence of numerous external links suggests an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://yizhu580.com/ckfinder/userfiles/files/57157248033.pdf In PDF document text
    • https://www.groupenahno.com/wp-content/plugins/super-forms/uploads/php/files/uuc3n4r99c8co5frheup8g18ec/2572771165.pdfIn PDF document text
    • http://tubelessons.net/cms_images/file/lozudux.pdfIn PDF document text
    • http://www.naturhalles.fr/fckeditor/userfiles/file/mokonuvaxobaxuraborub.pdfIn PDF document text
    • https://emilline.dk/ckfinder/userfiles/files/fesanevozujamato.pdfIn PDF document text
    • http://kmkonsult.cz/userfiles/file/vugari.pdfIn PDF document text
    • https://ensasoft.com.tr/wp-content/plugins/super-forms/uploads/php/files/0d0jogdh7h11bvpij5pjjd75j2/53068182347.pdfIn PDF document text
    • https://www.ayersworthglen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bd0402c24cc---nozefu.pdfIn PDF document text
    • https://motelandratecuci.ro/userfiles/file/mafevap.pdfIn PDF document text
    • http://demirtepe.org/userfiles/file/vuxosepuzabolimu.pdfIn PDF document text
    • http://emblem4home.com/UserFiles/Member/File/42180805403.pdfIn PDF document text
    • https://phukienbep.net/media/files/gosilibavuzuwajipu.pdfIn PDF document text
    • https://ateneoarbonaida.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d6279608125---37853798872.pdfIn PDF document text
    • http://amdind.com/userfiles/file/bitimabosisupukezubo.pdfIn PDF document text
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/8lu4gk9172dcrf18p5eqek6jt6/filitevokijureva.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/73fefc11e4ef9d399e2dfa4df9072ace/zijabi.pdfIn PDF document text
    • https://advance-pack.com/editor_upload/file/31302818213.pdfIn PDF document text
    • http://amouage-salon.ru/admin/ckfinder/userfiles/files/fakivasibogigokazulo.pdfIn PDF document text
    • https://dp-engineers.com/admin/userfiles/file/29889805318.pdfIn PDF document text
    • http://parquessolaresdenavarra.com/userfiles/files/77125222664.pdfIn PDF document text
    • https://daluxerealty.com/wp-content/plugins/super-forms/uploads/php/files/41k23ccbj7vnih6cj3r6q8luo0/38001062646.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=arifureta+after+story+2+pdfPDF link annotation
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/c4f2384063518972d277edf95d15c78c/86029731053.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_off0000b929.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB929 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d13b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD13B 17912 bytes
SHA-256: d4657887bbab5e768d8edc1a2cbd3ea454265780e3ee510a6d359920dc2c92ef
font_02_sfnt_off0000fe6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE6A 10656 bytes
SHA-256: 3d143be9579364323f66f1c1c88625a5fc0685901e7a779f2043f3e55d62ba82

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