CVE-2002-1557 in ONS15327
Summary
by MITRE
Cisco ONS15454 and ONS15327 running ONS before 3.4 allows attackers to cause a denial of service (reset to TCC, TCC+, TCCi or XTC) via a malformed HTTP request that does not contain a leading / (slash) character.
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Analysis
by VulDB Data Team • 05/29/2019
The vulnerability identified as CVE-2002-1557 affects Cisco ONS 15454 and ONS 15327 optical network switches operating with ONS software versions prior to 3.4. These network devices are critical components in telecommunications infrastructure, providing optical transport and switching capabilities for high-speed data transmission across long distances. The affected systems operate within the core network infrastructure of service providers and enterprises, making their reliability and stability paramount to network operations. The vulnerability specifically targets the HTTP server implementation within these network switches, which serves as a management interface for administrators to configure and monitor the devices remotely.
The technical flaw resides in the HTTP request parsing mechanism of the affected Cisco ONS devices. When processing incoming HTTP requests, the system fails to properly validate the format of the request line, specifically requiring a leading slash character to indicate the resource being requested. This validation weakness allows attackers to craft malformed HTTP requests that lack the required leading slash character, causing the HTTP server to behave unpredictably. The vulnerability is classified as a buffer over-read or improper input validation issue, where the system attempts to process the malformed request without proper boundary checking. According to CWE standards, this represents a weakness in input validation and improper handling of malformed data. The flaw essentially creates a parsing error that leads to system instability.
The operational impact of this vulnerability is significant as it can result in a complete denial of service condition for the affected network switch. When an attacker successfully exploits this vulnerability, the target device experiences a reset operation that affects critical components including the TCC (Transport Control Card), TCC+, TCCi, or XTC (eXtended Transport Card) modules. These components control the optical transport functions and data switching capabilities of the network device, meaning the reset operation effectively takes the switch offline and disrupts network services. The denial of service affects not only the management interface but also potentially impacts the data transport functions, causing cascading effects throughout the network infrastructure. This vulnerability can be exploited remotely without authentication, making it particularly dangerous in network environments where these devices are accessible from external networks.
Mitigation strategies for this vulnerability should focus on immediate software updates and network segmentation. Organizations must upgrade their Cisco ONS 15454 and ONS 15327 devices to software version 3.4 or later, which contains the necessary patches to address the HTTP request parsing flaw. Network administrators should also implement access controls to restrict HTTP management access to only trusted administrative networks and consider disabling HTTP management interfaces where possible, preferring more secure protocols like HTTPS or SSH for remote management. The ATT&CK framework categorizes this vulnerability under T1190 - Exploit Public-Facing Application, highlighting the need for proper network segmentation and monitoring of management interfaces. Additionally, implementing intrusion detection systems to monitor for malformed HTTP requests and establishing network access control lists can help detect and prevent exploitation attempts. Regular vulnerability assessments and security audits should be conducted to ensure all network infrastructure components remain protected against similar vulnerabilities.