What’s Vulnerable › Vulnerabilities

CVE-2001-0669

• Severity: high (CVSS 7.5 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2001-10-30 · updated 2026-06-16

Description

Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Catalyst 6000 Intrusion Detection System Module, (3) Dragon Sensor 4.x, (4) Snort before 1.8.1, (5) ISS RealSecure Network Sensor 5.x and 6.x before XPU 3.2, and (6) ISS RealSecure Server Sensor 5.5 and 6.0 for Windows, allow remote attackers to evade detection of HTTP attacks via non-standard "%u" Unicode encoding of ASCII characters in the requested URL.

Affected products

• Cisco Catalyst 6000 Intrusion Detection System Module: all versions
• Cisco Secure Intrusion Detection System: all versions
• Enterasys Dragon: 4.x
• ISS Realsecure Network Sensor: 5.x, 6.x
• ISS Realsecure Server Sensor: 5.5, 6.0
• Snort: 1.8.1

References

• http://marc.info/?l=bugtraq&m=99972950200602&w=2
• http://www.cisco.com/warp/public/707/cisco-intrusion-detection-obfuscation-vuln-pub.shtml
• http://www.kb.cert.org/vuls/id/548515
• http://www.securityfocus.com/bid/3292
• http://xforce.iss.net/alerts/advise95.php
• http://marc.info/?l=bugtraq&m=99972950200602&w=2
• http://www.cisco.com/warp/public/707/cisco-intrusion-detection-obfuscation-vuln-pub.shtml
• http://www.kb.cert.org/vuls/id/548515
• http://www.securityfocus.com/bid/3292
• http://xforce.iss.net/alerts/advise95.php

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