Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb4fa7c017af7c90…

MALICIOUS

PDF

97.6 KB Created: 2021-09-20 11:06:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 308e888c2ee9dc77452267c9d685ff20 SHA-1: 1ff5cd85162d31335fd17c598ebc5d21be484f36 SHA-256: cb4fa7c017af7c90331bb6f46e509ce82202d889aafc3b4a7033f7f23174b673
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to PDF files on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating the PDF is used to host many links on disposable domains. While no scripts were explicitly extracted, the nature of the embedded URLs and the detection suggests it's likely used as a lure for phishing or to download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://printsolutions.printsolutions.bg/uploads/wysiwyg/files/zowapogugopuwejase.pdf In PDF document text
    • https://perfecthospital.org/FCKeditor/file/4264985046.pdfIn PDF document text
    • https://am-system.eu/ckfinder/userfiles/files/1269407710.pdfIn PDF document text
    • https://rusepress.com/uploads/wysiwyg/files/depapalebujarunagodem.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1612eca6700ae9---xubenunig.pdfIn PDF document text
    • https://buzyhub.com/files/52073207542.pdfIn PDF document text
    • http://klinok-saintp.ru/files/29269174516.pdfIn PDF document text
    • https://tekartltd.com/upload/files/57557122091.pdfIn PDF document text
    • http://sk4education.com/ckfinder/userfiles/files/mifetiwoxumitulefodanaluf.pdfIn PDF document text
    • http://hairtransplantmangalore.com/uploaded_files/userfiles/files/81751579233.pdfIn PDF document text
    • http://qianxish.com/ckfind_image/files/50639153118.pdfIn PDF document text
    • http://apsencollege.org/test/fckeditor/file/wufebitirujudogex.pdfIn PDF document text
    • https://soi.icami.mx/ckfinder/userfiles/files/lenupaxigideberevubumulax.pdfIn PDF document text
    • http://nowator-zpu.pl/userfiles/file/61329247293.pdfIn PDF document text
    • http://fd-health.com/upload/ckeditor/files/pegatedepujapivejavugizes.pdfIn PDF document text
    • https://heks-tech.com/app/webroot/userfiles/files/muratabenijaxulo.pdfIn PDF document text
    • https://francoisdaulte.com/ckfinder/userfiles/files/72565441298.pdfIn PDF document text
    • http://abwjefferson.com/uploads/files/napugupole.pdfIn PDF document text
    • https://glycocalyx.nl/userfiles/image/file/48871697478.pdfIn PDF document text
    • http://livingkaneohe.com/userimages/niletikazebakafabo.pdfIn PDF document text
    • http://uforoi.com/app/webroot/uploads/files/96479196996.pdfIn PDF document text
    • https://www.sophrologue-nimes.fr/upload/news/files/92451769825.pdfIn PDF document text
    • http://www.bridalchapel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140fa41f3095---79836436346.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=grey%27s+anatomy+season+17+episode+1+onlinePDF 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_off00011826.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11826 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00013038.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13038 18052 bytes
SHA-256: 52832910c168be10c0649a6a174b510aed768122b1a2d0a986a6f9f77e327a68
font_02_sfnt_off00015f4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15F4F 10840 bytes
SHA-256: e609854f726e9e5e4124e616962ad5b04939400fc0b2561c06efd69583fe86f1