Malicious PDF — malware analysis report

Static analysis result for SHA-256 527c23c07bd1e394…

MALICIOUS

PDF

67.8 KB Created: 2021-09-17 22:56:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 4bdd05d42abc35d38d6c04918847bd10 SHA-1: 726b6678ba94a3a74a803348dce7c2d666c5321d SHA-256: 527c23c07bd1e3941d6c573e32286b244b53a5a7cb6393b2ef9550645d061749
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains numerous external links, many hosted on compromised or disposable domains, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this. The primary attack pattern involves luring users via these links, likely for phishing or to download further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.5990

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
  • 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
  • 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://pistant.ru/uplcv?utm_term=turn+off+ads+miui+12 PDF link annotation
    • http://esllearningbydesign.com/app/webroot/files/file/49754683650.pdfIn PDF document text
    • http://mimarathi.live/assets/ckfinder/core/connector/php/uploads/files/buruve.pdfIn PDF document text
    • https://f2h63c2.ip4secure.net/upload/files/funetuwudok.pdfIn PDF document text
    • https://khanoomhoteli.com/basefile/khanoomhotelicom/files/70039395918.pdfIn PDF document text
    • http://www.pethouse.es/ckfinder/userfiles/files/51479884552.pdfIn PDF document text
    • https://milorem-service.ru/userfiles/file/gawepipominefefog.pdfIn PDF document text
    • http://lifecontinues.ru/images/files/bazajelotesafix.pdfIn PDF document text
    • http://kystop.com/wp-content/plugins/super-forms/uploads/php/files/16de8a783a3452726ba8d155a96dcfac/94138979269.pdfIn PDF document text
    • http://jlicentral.com/images/authors/file/wolozagomugow.pdfIn PDF document text
    • http://chono.mn/uploads/userfiles/files/44627776113.pdfIn PDF document text
    • https://galerieportelouise.be/userfiles/files/49061414210.pdfIn PDF document text
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/16141771898106---4373155164.pdfIn PDF document text
    • http://vom-ragnaroek.de/uploads/file/ropidak.pdfIn PDF document text
    • http://www.nisbd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139e689c4b76---jowovipizagexekadinawekef.pdfIn PDF document text
    • http://alotercuman.com/ckfinder/userfiles/files/judaritexul.pdfIn PDF document text
    • https://www.actionconstructionjax.com/wp-content/plugins/super-forms/uploads/php/files/5dcbaf3308e9d07ecdd27bc1fe07fb72/tiloxisavopofoboji.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/161419c32ba179---89034906401.pdfIn PDF document text
    • http://tangiahoang.com/skinkorea/Images_upload/files/2525241001.pdfIn PDF document text
    • https://huanghecables.com/d/files/74731460029.pdfIn PDF document text
    • http://siripanyalamphun.com/user_img/files/betuguli.pdfIn PDF document text
    • http://akvatoria.by/UserFiles/files/43044204613.pdfIn PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d9ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9CA 10472 bytes
SHA-256: 091eeee6f94df2c4456c802574abd35e5440273d504486e61975755abca6fdb3
font_01_sfnt_off0000f19a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF19A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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