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.
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Exploit-DB 1
- Cisco Secure IDS 2.0/3.0 / Snort 1.x / ISS RealSecure 5/6 / NFR 5.0 - Encoded IIS Detection Evasion EDB-21100 · remote · Sep 5, 2001 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
References
- VU#548515 third-party-advisory
- 3292 vdb-entry
- 20010905 Cisco Secure Intrusion Detection System Signature Obfuscation Vulnerability vendor-advisory
- 20010905 Multiple Vendor IDS Unicode Bypass Vulnerability third-party-advisory
- 20010905 %u encoding IDS bypass vulnerability mailing-list