Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca23bbc610e89b92…

MALICIOUS

PDF

82.3 KB Created: 2021-09-03 20:31:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: dec507353d2c8b0b861012f33bc5ad0e SHA-1: 43d015233a86f5e8bcbd42832e54082da250c314 SHA-256: ca23bbc610e89b92ce72f59a08fb2695f3f578c2506ff36f616869b1bd36d985
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. It contains numerous links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://www.chesapeake-lighting.com/wp-content/plugins/super-forms/uploads/php/files/eb32e4323e9a171235bd0f4d7b4037e1/rukogonunakixezodegin.pdf In PDF document text
    • http://rhondachem.com/d/files/lipafu.pdfIn PDF document text
    • http://grawerlik.pl/userfiles/file/midozavadoxoberepos.pdfIn PDF document text
    • http://makinsushi.com/uploads/files/tumufomakuvavokajenese.pdfIn PDF document text
    • https://postscriptproductions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bc87ecb4818---nerokumumera.pdfIn PDF document text
    • http://www.hj-bouwt.be/wp-content/plugins/formcraft/file-upload/server/content/files/160705da13316f---18271902940.pdfIn PDF document text
    • http://moyamoya.center/images/hand_uploaded/files/vidanisa.pdfIn PDF document text
    • http://esistore.be/userfiles/file/guvoza.pdfIn PDF document text
    • http://xiaohecollege.com/d/files/mulufuwaxakoxaxadup.pdfIn PDF document text
    • http://scissortailfarms.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b0efa7f1bd---39887672061.pdfIn PDF document text
    • http://panyuchen.com/ckfinder/userfiles/site_eachfun_com/files/suwanetigem.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b222c03cf23---89353183084.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d9f628b552---fanuzaroxo.pdfIn PDF document text
    • https://arizonapoolcontractor.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a1f50decc46---39801848430.pdfIn PDF document text
    • http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1609b76dfac760---3150785205.pdfIn PDF document text
    • http://simonide.org/userfiles/file/sewimemagakomesin.pdfIn PDF document text
    • http://pensionpoint.cz/userfiles/files/junap.pdfIn PDF document text
    • https://webmakler.org/userfiles/file/gejupanimitepu.pdfIn PDF document text
    • https://betonwerkendejonge.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160b24f0a2bbad---81598142786.pdfIn PDF document text
    • https://wolfgang-photography.com/userfiles/files/49936555236.pdfIn PDF document text
    • http://perchegouet.com/ckfinder/userfiles/files/bevoj.pdfIn PDF document text
    • https://alnahamgroup.com/userfiles/file/dogosubuva.pdfIn PDF document text
    • https://mytutr.com/wp-content/plugins/super-forms/uploads/php/files/3062099c9e35343db33e2f0b24336307/fepow.pdfIn PDF document text
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c6b9f2eb4cd---lexevidux.pdfIn PDF document text
    • http://skup-laptopow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb118473315---vabepebire.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=us+constitution+2nd+amendment+pdfPDF link annotation
    • 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_off0000dd51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD51 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f563.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF563 17884 bytes
SHA-256: f36a3e81874ee8a84e367de77522e6fa1a2997bd1f8c2dda68709f4125c1b153
font_02_sfnt_off0001223e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1223E 10860 bytes
SHA-256: 1c6e4fa7ee39d794d6ceeead569e641a4674d83050e19c3431994ba718861cd3