CVE-2007-1251 in Netrek Vanilla Server
Summary
by MITRE
Format string vulnerability in the new_warning function in ntserv/warning.c for Netrek Vanilla Server 2.12.0, when EVENTLOG is enabled, allows remote attackers to cause a denial of service (crash) or execute arbitrary code via format string specifiers in the message handling.
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Analysis
by VulDB Data Team • 03/26/2019
The vulnerability described in CVE-2007-1251 represents a critical format string vulnerability within the Netrek Vanilla Server version 2.12.0, specifically within the new_warning function located in ntserv/warning.c. This flaw emerges when the EVENTLOG feature is enabled, creating a dangerous condition that exposes the server to remote exploitation. The vulnerability stems from improper handling of user-supplied input within the format string processing mechanism, where attacker-controlled data is directly incorporated into printf-style function calls without adequate sanitization or validation. The affected software component operates as part of the networked multiplayer game server infrastructure, where it processes various message types and logs warnings to the system event log. When EVENTLOG is active, the server's warning function becomes susceptible to manipulation through carefully crafted input sequences that contain format specifiers.
The technical exploitation of this vulnerability occurs when a remote attacker sends specially constructed messages to the Netrek server that contain format string specifiers such as %s, %d, or %x within the warning message payload. These specifiers, when processed by the vulnerable new_warning function, can cause the server to read from arbitrary memory locations or write data to specific memory addresses, depending on the nature of the format string manipulation. The vulnerability manifests in two primary attack vectors: denial of service through server crashes and potential arbitrary code execution on the target system. When the server attempts to process these malformed format strings, it can dereference invalid memory addresses or overwrite critical program variables, leading to unpredictable behavior including immediate termination of the server process. The root cause of this issue aligns with CWE-134, which specifically addresses the use of format strings with user-supplied data without proper validation or sanitization, making it a classic example of insecure coding practices in system software development.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable complete system compromise. Network administrators and security professionals must recognize that an attacker who successfully exploits this vulnerability can gain unauthorized access to the server's execution environment, potentially leading to privilege escalation, data theft, or further network infiltration. The remote nature of the attack means that adversaries can exploit this weakness from anywhere on the network without requiring local system access or authentication. The vulnerability affects the integrity and availability of the Netrek game server infrastructure, which could impact multiplayer gaming experiences and potentially provide attackers with a foothold for broader network attacks. Organizations running this version of the Netrek server should consider this vulnerability as a high-priority threat requiring immediate remediation, as the potential for arbitrary code execution creates a significant risk to overall system security. The ATT&CK framework would categorize this vulnerability under the technique of "Format String Attack" within the broader category of "Exploitation for Privilege Escalation" and "Remote Code Execution" tactics, making it a particularly dangerous weakness in networked server software.
The recommended mitigations for this vulnerability include immediate patching of the Netrek Vanilla Server to a version that properly handles format string arguments, implementing input validation and sanitization measures within the warning function, and disabling the EVENTLOG feature if it is not essential for operational requirements. System administrators should also consider implementing network segmentation and access controls to limit exposure to this vulnerability. The vulnerability demonstrates the critical importance of proper input validation and the dangers of using user-supplied data directly in format string operations, serving as a reminder of fundamental security principles in software development. Organizations should conduct comprehensive security reviews of their legacy systems to identify similar vulnerabilities and establish robust coding practices that prevent such issues from occurring in future software releases.