Malicious PDF — malware analysis report

Static analysis result for SHA-256 16c73634a26686c2…

MALICIOUS

PDF

81.1 KB Created: 2021-09-07 03:14:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 0f720caafe29c6a1e7df05fd581c1d93 SHA-1: d03067b8b117f2c9c10f063a11ec173fc2814501 SHA-256: 16c73634a26686c2fb5f3061d7ba2c33bc1e839a4025da57cd0a838a61065916
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URLs, many hosted on compromised CMS upload directories, suggesting a link farm used for phishing or malware distribution. The PDF structure itself does not contain readable content, but the presence of embedded URLs and the overall heuristic firings point towards a malicious document designed to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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://cructi.ru/uplcv?utm_term=challenging+core+beliefs+worksheet+pdf PDF link annotation
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9329cd0fc6---27716237767.pdfIn PDF document text
    • http://mamnonhieutrung.edu.vn/ckfinder/userfiles/files/89010315163.pdfIn PDF document text
    • https://hafa-verein.de/wp-content/plugins/super-forms/uploads/php/files/9257c5fc7adb0655f9d80c55113aa352/93080749568.pdfIn PDF document text
    • http://andreevmag.com/wp-content/plugins/super-forms/uploads/php/files/3bd3a075cd400598805458d6018db529/95970389573.pdfIn PDF document text
    • http://mcelvain2020reunion.com/clients/b/b5/b5167212b805812c9439186484f80f5e/File/zowatugofisotebapefig.pdfIn PDF document text
    • http://stellarp.com/userfiles/files/30859645718.pdfIn PDF document text
    • http://28777886.com/Lpf/UPFILE/userfiles/files/40802100963.pdfIn PDF document text
    • https://www.kcequipment.com.au/wp-content/plugins/super-forms/uploads/php/files/0314cd296403a8600b6cc13caa572ca0/11985735968.pdfIn PDF document text
    • http://quadocdao.vn/uploads/files/wibuwek.pdfIn PDF document text
    • http://kondicionery-vidnoe.ru/upload_picture/file/68254152894.pdfIn PDF document text
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/13ea5a6d8bcb6c06dbaeda1efac628a9/xabirakizilasisiloranobop.pdfIn PDF document text
    • https://riverasphotovideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d7d9a5c9bf---wujuguvewajalud.pdfIn PDF document text
    • https://jbdclothiers.net/emailer/userfiles/file/66836072927.pdfIn PDF document text
    • http://nhadep30giay.com/uploads/image/files/17467692678.pdfIn PDF document text
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1611122f3d095c---49703594476.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16079337fbfc60---64037104974.pdfIn PDF document text
    • https://powermailer.in/userfiles/file/korexow.pdfIn PDF document text
    • https://www.sblending.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160bae58e8952a---53258895504.pdfIn PDF document text
    • http://kraski-chernila.ru/resources/file/4331198961.pdfIn PDF document text
    • http://akademia-jedenastka.pl/zdjecia/fck/file/29922427498.pdfIn PDF document text
    • http://yonseri.org/userfiles/files/97660825126.pdfIn PDF document text
    • http://lovewhereyoulv.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/0ba6a6b6f995420f0842271849813e1c/kumujetuzotidefuxadeselen.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_off0000d949.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD949 11248 bytes
SHA-256: 278ca01c56e603528ed33d2e9d4be92b19c35dbc5bfe12f96152eed311406c34
font_01_sfnt_off0000f345.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF345 17028 bytes
SHA-256: 3336bdc50d0d5265682e47827c11339ef0eca817c25d5e6715f0681317fac008
font_02_sfnt_off00011e88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E88 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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