Malicious PDF — malware analysis report

Static analysis result for SHA-256 537e1dc4371e396a…

MALICIOUS

PDF

81.1 KB Created: 2021-08-21 03:49:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ce658b9a665d1cb70b893da6d5d6f0e0 SHA-1: 0b2710e19779a9f72e26266752d1ecd5da66d349 SHA-256: 537e1dc4371e396a9b5ae2cb303e8948049e5efb284ba7c18a181040779c2cd7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links pointing to compromised websites and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of embedded URLs and the nature of the heuristics indicate an attempt to lure users to external sites, likely for further exploitation or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

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://jollytime.ru/wp-content/plugins/super-forms/uploads/php/files/23b3699b69dc0811bbd242fe74da2c47/81026184350.pdf
    • https://www.borzabadi.com/ckfinder/userfiles/files/sugeka.pdf
    • http://sieckultury.pl/wp-content/plugins/super-forms/uploads/php/files/1627087c2aa561a936b1c26c5526e780/64747459620.pdf
    • http://abwnickersonplaza.com/uploads/files/41313061614.pdf
    • http://drtamerturan.com/file/17990611122.pdf
    • https://tidurmalam.com/contents//files/zugukamitonitaloz.pdf
    • https://www.idahomedia.com/wp-content/plugins/super-forms/uploads/php/files/dd80b283faf7b7ae74889ddafa9632bb/27217838398.pdf
    • http://aurastaffing.es/upload/file/75186095092.pdf
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/abbf84916303239c12e59994c163565b/jokinuxe.pdf
    • https://tsydesign.com/userfiles/jws/files/39886302043.pdf
    • http://de.ruben.pl/ckfinder/userfiles/files/23124191021.pdf
    • http://laboratorioshamalab.com/userfiles/file/vitavogevukudew.pdf
    • https://people11people.gr/uploads/File/68477517491.pdf
    • https://nikosdimos.gr/userfiles/file/8740686493.pdf
    • http://kursadowicz.pl/Upload/file/90431516974.pdf
    • http://misosmile.com/upload/editor/files/nuwir.pdf
    • https://soba05.org/wp-content/plugins/super-forms/uploads/php/files/ee56937e8760b6d85a6356fe2ec6d3a0/xepogijok.pdf
    • http://costruzionibulagna.it/userfiles/files/74064137629.pdf
    • http://massiimo.com/piceditor/file/lowabepobirat.pdf
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607afc3d1a166---dubezexasowirilatinibad.pdf
    • http://manpukulivermore.com/uploads/files/dowojipovivumogelirap.pdf
    • http://turar-mussin.com/userfiles/File/44951692726.pdf
    • http://broomfield82.com/clients/4/48/489ff1710263d1ca947d92387d56c809/File/dofawofalox.pdf
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160870b766236f---divoxiwimiwut.pdf
    • https://delaneyllc.com/ckfinder/userfiles/files/41944618552.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+write+a+letter+of+responsibility
    • 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_off0000dbbf.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDBBF 16792 bytes
font_01_sfnt_off0000f3d6.bin
3f2c4273e735e2ec8e47beddb69c804abeaf8ee9b7700e3fecb7741c645f1619
pdf-font-stream PDF embedded font (sfnt) at offset 0xF3D6 10680 bytes
font_02_sfnt_off00010c41.bin
9319bcc8fd9a95ddb33fcf94c371d166a670f1857d3e5b6fac0c5ee5728c0ec6
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C41 16144 bytes