Malicious PDF — malware analysis report

Static analysis result for SHA-256 c6b8f901732e9cd8…

MALICIOUS

PDF

76.3 KB Created: 2021-09-18 22:49:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 7916d89758dad30ed6d5eee8aa28f673 SHA-1: bbf01ec4b9d148ac9c5045b02b66bd594a9106fe SHA-256: c6b8f901732e9cd8bb0b5a48c9c81ba966c6c262bf554fdbc7d14640c443d55f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by a machine learning classifier and ClamAV as malicious, indicating a phishing or trojan threat. It contains numerous external links, many pointing to compromised CMS upload directories, suggesting a tactic to distribute malicious content or phish users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, but the presence of external links is the primary indicator of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://crysiq.ru/uplcv?utm_term=how+to+put+a+mac+into+recovery+mode PDF link annotation
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/17869196723.pdfIn PDF document text
    • https://etcbt.com/userfiles/file/goxusidiziwisifugol.pdfIn PDF document text
    • https://agriplan-rs.com/dados/ckfinder/files/18865608121.pdfIn PDF document text
    • https://relaxationplusmn.com/wp-content/plugins/super-forms/uploads/php/files/f51023338a8697d58f296bc8bd3e7f5f/49632182725.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/161333b7e60067---wilufavukizinevoluwixaxos.pdfIn PDF document text
    • http://franklcalabreseattorney.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/kekupadonowipiga.pdfIn PDF document text
    • http://swaptoys.org/ckeditor/uploads/files/38756501218.pdfIn PDF document text
    • http://mateuszkucharski.pl/admin/file/jozukunokonugurozav.pdfIn PDF document text
    • https://www.hdcorp.com.br/wp-content/plugins/super-forms/uploads/php/files/9qf5ree9dartrefhjlgkva99ut/57971623269.pdfIn PDF document text
    • https://sunriseinnjasper.com/nbloom/fckuploads/file/nojesur.pdfIn PDF document text
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/73fe6501527929a43ec25c1c8beaa5e9/90859674016.pdfIn PDF document text
    • http://colleges-in-tamilnadu.com/FCKeditor/userfiles/file/nukiworev.pdfIn PDF document text
    • http://xn--vb0b83rba554gca.kr/page_data/file/20210912074347.pdfIn PDF document text
    • https://creationstationdance.com/wp-content/plugins/formcraft/file-upload/server/content/files/16145a79dbd3fc---22819251607.pdfIn PDF document text
    • http://polimak.pl/userfiles/file/nagafebi.pdfIn PDF document text
    • http://elliptical-trainers.ru/ckfinder/userfiles/files/parufipifaviwe.pdfIn PDF document text
    • http://interstyle.org/content/xuploadimages/file/50931435049.pdfIn PDF document text
    • http://alsace.annuaire-regional.com/ckfinder/userfiles/files/rexedidila.pdfIn PDF document text
    • https://wotfiles.com/ckfinder/userfiles/files/wawesubebanevelumamopeved.pdfIn PDF document text
    • http://mishor-uvk.com/uploads/files/fizijigadebepofu.pdfIn PDF document text
    • https://reviewz.eu/app/webroot/files/userfiles/files/90267489903.pdfIn PDF document text
    • https://bloomland.com/sites/bloomland.com/files/69292915741.pdfIn PDF document text
    • http://constantcontinuity.com/membership/data/files/retemenefujixinuso.pdfIn PDF document text
    • https://goodluckfishing.com/ckfinder/userfiles/files/tojuxebuzolik.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_off0000c89d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC89D 16188 bytes
SHA-256: 7e32c982c0cec47585f709ad2b8773aa3d4271d051603cc9e13b05f76b62933d
font_01_sfnt_off0000f20b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF20B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010a22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A22 10820 bytes
SHA-256: 2b987bf2e01c1ee0d309fb61e83ee5c2327851330bcab7320a463551b582aaaf

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