Malicious PDF — malware analysis report

Static analysis result for SHA-256 53e0a21842e6c053…

MALICIOUS

PDF

87.7 KB Created: 2021-09-19 19:49:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7fd678d963979a7d16b551618ac9f1d2 SHA-1: 8ecf354574115c839846f922d2e4041ce71597da SHA-256: 53e0a21842e6c053711ccbad9916b918f8a4cb67cdea3abca609fc274f9f4b3f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file identified as malicious by ML classifiers and ClamAV. It contains numerous embedded URLs, many of which are associated with link farms and disposable hosting, suggesting a phishing or malware distribution scheme. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically indicates the document's structure is designed to host many links on potentially untrustworthy domains. No scripts were extracted from this sample, but the presence of many external URIs points to an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://medvor.ru/uplcv?utm_term=nexus+5+android+11
    • http://www.badischer-kunstverein.de/ckfinder/userfiles/files/11301330904.pdf
    • http://luatsugiadinhviet.com/upload/ck/files/vaburuwunonoxukesilojado.pdf
    • https://silky.ae/images/bulk_images/files/nilinefupuzuwokabavagewi.pdf
    • http://xn--90afqerdlt1f.xn--p1ai/admin/ckfinder/userfiles/files/fesim.pdf
    • http://roycraft.ca/userfiles/file/2252374027.pdf
    • http://aprt1day.ru/file/66773381196.pdf
    • https://takitech.hu/userfiles/file/82859587732.pdf
    • http://ventss.ru/userfiles/files/96037349445.pdf
    • http://businessplan-capalpha.eu/mbp/upload/images/images/upload/ckfinder/vixetab.pdf
    • http://cerrutistudio.eu/userfiles/files/68760436030.pdf
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/161351be8d8d95---38904567262.pdf
    • https://demo-calson.garment-pro.com/ckfinder/userfiles/files/32095078951.pdf
    • https://ltes2.tw-goods.com/UserFiles/files/79340192090.pdf
    • https://ldoris.com/upfile/files/20210913062540.pdf
    • https://ewdel.cz/ckfinder/userfiles/files/baxefalur.pdf
    • http://holzweiss.at/zufukemasa.pdf
    • http://greathorserider.com/ckfinder/userfiles/files/tukemevuzasobokoxivedam.pdf
    • https://odlingfamily.com/userfiles/file/22965941582.pdf
    • https://wodepcb.cn/uploadfiles/files/95224035715.pdf
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/161362cae683c1---lujibedawi.pdf
    • http://gdfsztal.com/uploadfile/files/2161938652.pdf
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/161386d1ac9234---77816148166.pdf
    • http://runbo.net/upfiles/files/16319813785035.pdf
    • http://7serve.org/userfiles/file/20210917114144.pdf
    • http://sarljarry.com/userfiles/file/20833010335.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f12d.bin
b39bd2e63fc0b2bd0b06659fd2d99db56d1384880daedf99a4836595321ea54e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF12D 18328 bytes
font_01_sfnt_off00012109.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12109 16792 bytes
font_02_sfnt_off00013920.bin
595bf9805db6be90463f6e07a628c9e4b7cbd84a317ed3a0a54d1f88bbe58158		 pdf-font-stream PDF embedded font (sfnt) at offset 0x13920 10460 bytes

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