Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8cd21e1751a828a…

MALICIOUS

PDF

78.3 KB Created: 2021-09-17 14:35:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 759c2cd7118f313c7f8b9ed0aa2f47c6 SHA-1: 9e711673c1a5b8a64e13be81a04daf5f148415d5 SHA-256: a8cd21e1751a828ab028457169fb872fa55d2ccb0bfcdbff796abc4a32f817f2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to compromised CMS upload directories, suggesting it functions as a link farm. The primary purpose appears to be redirecting users to external sites, potentially for phishing or to download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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://garglob.ru/uplcv?utm_term=download+open+card+idn+poker PDF link annotation
    • http://indiebookoftheday.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a341758b43---57163820575.pdfIn PDF document text
    • https://cradlegold.com/wp-content/plugins/super-forms/uploads/php/files/587hngpgid943o79putr31ee5k/damemabenubove.pdfIn PDF document text
    • http://onsijsselstein.nl/userfiles/files/xovivebujifigus.pdfIn PDF document text
    • https://markmont.eu/editor_uploads/system/files/23090441444.pdfIn PDF document text
    • http://sacoorhealth.pt/site/upload/file/7208458495.pdfIn PDF document text
    • http://louisefarmersmith.com/admin/ckeditor/ckfinder/userfiles/files/wufekibogixulotuf.pdfIn PDF document text
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/6djt41rpjmbn32j4vgk6lv32q5/tizosoligizanosav.pdfIn PDF document text
    • https://tlproduct.com/userfiles/file/23736364935.pdfIn PDF document text
    • https://chetanaus.org/bheru/uploadfiles/file/didil.pdfIn PDF document text
    • http://bbhshipyard.com/userfiles/file/rukipuzagedibetosixezaja.pdfIn PDF document text
    • https://alpasol.e-giant.net/upload/files/73391148525.pdfIn PDF document text
    • http://gaudi.tw/upload/files/31447991596.pdfIn PDF document text
    • http://aquarium-kochi.com/app/webroot/ckfinder/userfiles/files/50647127368.pdfIn PDF document text
    • http://montesantangelo.it/files/files/pamegejax.pdfIn PDF document text
    • https://hanyauntuktesting.com/contents/files/xesiwokipobiremujuro.pdfIn PDF document text
    • http://csc-021.com/userfiles/file/20210914023428_jsntad.pdfIn PDF document text
    • https://fontaine-eva.fr/userfiles/files/43762016157.pdfIn PDF document text
    • http://hitechdentalhouston.com/uploads/files/70587259089.pdfIn PDF document text
    • https://safetyhanoi.com/userfiles/file/pepebonepefiwudawenodune.pdfIn PDF document text
    • http://suliaok.com/v15/Upload/file/202196938308388.pdfIn PDF document text
    • http://wu-pao.com/upfiles/editor/files/43527677941.pdfIn PDF document text
    • http://sh8ke.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614188a921491---17004484611.pdfIn PDF document text
    • http://canoeing.by/pics/files/rutivoxaje.pdfIn PDF document text
    • http://nanumed.ro/uploads/files/15800898487.pdfIn PDF document text
    • https://candbco.com/ckfinder/userfiles/files/gagexumikobatop.pdfIn PDF document text
    • http://fuzoku-kyujin.jp/ckfinder/userfiles/files/23978989710.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_off0000cd26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD26 10420 bytes
SHA-256: c03c247db5695bdd13fffc9ab42dcb92f2ecdb8594bd50194ca583e10e2ba0f8
font_01_sfnt_off0000e4d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4D3 17816 bytes
SHA-256: 766cea399602b51a6cc391c4a830ccc977b40e8f71e7c72c18903531236f1b2e
font_02_sfnt_off000112f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112F6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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