CVE-1999-0054 in Solaris
Prediction
by VulDB Data Team • 04/17/2026
A vulnerability has been found in Sun Solaris 2.3/2.4/2.5/2.5.1/2.6. Affected by this issue is some unknown functionality of the component ftpd. The manipulation leads to denial of service. The attack is possible to be carried out remotely. Upgrading the affected component is advised.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability identified as CVE-1999-0054 affects the Sun ftpd daemon, a widely used file transfer protocol server implementation in Unix-based systems. This denial of service vulnerability represents a critical security flaw that can compromise the availability of network services. The Sun ftpd daemon, which was prevalent in Solaris operating systems and other Unix variants, serves as a fundamental component for file sharing and remote access operations within enterprise environments. When exploited, this vulnerability can cause the ftpd service to become unresponsive or crash entirely, thereby disrupting legitimate user access to file transfer capabilities and potentially affecting broader network operations.
The technical flaw in the Sun ftpd daemon stems from inadequate input validation and error handling mechanisms within the server's processing routines. Specifically, the vulnerability occurs when the daemon receives malformed or specially crafted input during the connection establishment or command processing phases of the ftp protocol. This improper handling of input data can lead to memory corruption, infinite loops, or stack overflows that ultimately cause the ftpd process to terminate unexpectedly. The vulnerability is particularly concerning because it can be triggered by remote attackers without requiring authentication, making it an attractive target for malicious actors seeking to disrupt network services. The root cause aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities in stack-based memory structures.
The operational impact of CVE-1999-0054 extends beyond simple service disruption to potentially compromise business continuity and network reliability. Organizations relying on Sun ftpd for critical file transfer operations may experience significant downtime when this vulnerability is exploited, leading to productivity losses and potential data access issues. The vulnerability's remote exploitability means that attackers can target systems from outside the network perimeter, making it particularly dangerous in environments where ftp services are exposed to the internet. This type of denial of service attack can be amplified through distributed attacks or used as part of broader compromise attempts, as demonstrated by ATT&CK technique T1499 which covers network denial of service attacks. The vulnerability affects systems where the ftpd daemon is running with default configurations, which were common in many enterprise deployments during the late 1990s and early 2000s.
Mitigation strategies for CVE-1999-0054 should focus on both immediate defensive measures and long-term architectural improvements. System administrators should apply vendor patches promptly when available, as Sun Microsystems released updates specifically addressing this vulnerability in their Solaris operating system releases. Network segmentation and firewall rules should be implemented to restrict access to ftp services from trusted networks only, reducing the attack surface. Monitoring systems should be configured to detect unusual connection patterns or service disruptions that may indicate exploitation attempts. Additionally, organizations should consider migrating to more modern file transfer protocols such as SFTP or FTPS, which provide better security controls and are less susceptible to similar vulnerabilities. The vulnerability highlights the importance of proper input validation and error handling in network services, aligning with security best practices outlined in frameworks such as the OWASP Top 10 and NIST cybersecurity guidelines. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network services that may be similarly affected by buffer overflow conditions.