CVE-1999-1175 is a high-severity vulnerability affecting the Web Cache Control Protocol (WCCP) implementation in Cisco Cache Engine for Cisco IOS version 11.2 and earlier. WCCP is a protocol designed to enable routers and switches to redirect web traffic to cache engines, improving web performance and reducing bandwidth usage. However, in the affected versions, WCCP does not implement any form of authentication or verification for incoming WCCP packets. This lack of authentication allows a remote attacker to send crafted WCCP packets to UDP port 2048 on vulnerable Cisco IOS devices, causing the device to redirect HTTP traffic to arbitrary hosts controlled by the attacker. Such redirection can lead to interception, manipulation, or denial of service of web traffic. The vulnerability impacts confidentiality, integrity, and availability of HTTP communications passing through the affected devices. The CVSS v2 score is 7.5 (high), reflecting the network vector (AV:N), low attack complexity (AC:L), no authentication required (Au:N), and impacts on confidentiality (C:P), integrity (I:P), and availability (A:P). No patches are available for this vulnerability, and there are no known exploits in the wild documented at this time. Given the age of the vulnerability and the affected IOS versions, modern Cisco devices are unlikely to be impacted, but legacy systems still in operation remain at risk. The vulnerability is particularly critical in environments where Cisco IOS devices are used as routers or switches handling HTTP traffic and where WCCP is enabled for web caching purposes.

For European organizations, exploitation of this vulnerability could lead to significant security risks including interception and redirection of sensitive HTTP traffic, potentially exposing confidential information or enabling man-in-the-middle attacks. Integrity of web traffic could be compromised by redirecting users to malicious servers, facilitating phishing or malware delivery. Availability could also be affected if traffic is redirected to non-responsive hosts, causing denial of service. Organizations relying on legacy Cisco IOS devices with WCCP enabled, especially in sectors such as finance, government, telecommunications, and critical infrastructure, face increased risk. The vulnerability could undermine trust in network communications and lead to regulatory compliance issues under GDPR if personal data is exposed. Since no patch is available, organizations must rely on mitigating controls to reduce exposure. The risk is heightened in environments where network segmentation is weak or where monitoring of UDP port 2048 traffic is not performed.

1. Disable WCCP on Cisco IOS devices if it is not strictly necessary, especially on legacy devices running IOS 11.2 or earlier. 2. If WCCP is required, isolate the network segments where WCCP traffic (UDP port 2048) is allowed, restricting it to trusted devices only via access control lists (ACLs) and firewall rules. 3. Implement strict ingress and egress filtering on network devices to block unauthorized WCCP packets from untrusted sources. 4. Monitor network traffic for unusual or unexpected WCCP packets, particularly those attempting to redirect HTTP traffic, using intrusion detection/prevention systems (IDS/IPS) with custom signatures for WCCP anomalies. 5. Plan and execute an upgrade strategy to move to supported Cisco IOS versions that include authentication or more secure implementations of WCCP. 6. Conduct regular network audits to identify legacy devices still running vulnerable IOS versions and assess the necessity of WCCP usage on those devices. 7. Employ network segmentation and zero-trust principles to limit the impact of any potential exploitation. 8. Educate network administrators about the risks of unauthenticated protocols and the importance of secure configurations.