CVE-2010-1676 in Tor
Summary
by MITRE
Heap-based buffer overflow in Tor before 0.2.1.28 and 0.2.2.x before 0.2.2.20-alpha allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via unspecified vectors.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 10/07/2021
The vulnerability identified as CVE-2010-1676 represents a critical heap-based buffer overflow within the Tor anonymity network software that affected versions prior to 0.2.1.28 and 0.2.2.x versions before 0.2.2.20-alpha. This flaw resides in the core daemon process of Tor, which is responsible for maintaining the network's routing infrastructure and ensuring secure communication between clients and servers. The buffer overflow occurs in the heap memory management system where malicious input can cause memory corruption that leads to unpredictable behavior. The vulnerability demonstrates characteristics consistent with CWE-121, heap-based buffer overflow, where insufficient bounds checking allows attackers to overwrite adjacent memory locations in the heap allocation region. This type of vulnerability is particularly dangerous in network services as it can be exploited remotely without authentication, making it a prime target for attackers seeking to compromise the anonymity infrastructure that millions of users rely upon for privacy protection.
The technical exploitation of this vulnerability involves crafting malicious input that triggers the buffer overflow condition during normal Tor daemon operations. When the vulnerable software processes malformed data, typically within network protocol handling or configuration parsing components, the heap memory allocation becomes corrupted. This corruption can manifest as stack smashing, memory pointer overwrites, or arbitrary memory location modifications that cause the daemon to crash or potentially execute arbitrary code. The attack surface is broad as the vulnerability affects core network processing functions that handle various types of incoming data from network connections, making it difficult to predict the exact exploitation vectors. The vulnerability's impact extends beyond simple denial of service as the heap corruption could potentially be leveraged for code execution, representing a serious threat to the integrity and security of the entire Tor network infrastructure.
The operational impact of CVE-2010-1676 is severe for the Tor ecosystem and its users who depend on the network for anonymous communication. When exploited, the vulnerability can cause daemon crashes that disrupt the anonymity network, forcing users to reconnect and potentially compromising their anonymity through connection patterns. The possibility of arbitrary code execution introduces additional risks where attackers could gain control over Tor relay nodes, potentially allowing them to monitor traffic, disrupt network operations, or even establish persistent backdoors within the anonymity infrastructure. This vulnerability directly impacts the core security model of Tor by potentially compromising the trust model that users place in the network. The attack can be conducted remotely without requiring any special privileges or authentication, making it particularly dangerous for relay operators who may unknowingly become compromised nodes. From an operational standpoint, this vulnerability would have required immediate patching across all affected Tor installations, creating significant operational challenges for maintaining network availability and security.
Mitigation strategies for CVE-2010-1676 primarily involve immediate software updates to versions 0.2.1.28 or 0.2.2.20-alpha and later, which contain the necessary memory bounds checking and heap management improvements. Network administrators should implement automated patch management systems to ensure all Tor installations are updated promptly. The vulnerability demonstrates characteristics that align with ATT&CK technique T1190, Exploit Public-Facing Application, where attackers target vulnerabilities in network services to gain unauthorized access. Organizations should also implement network monitoring to detect unusual daemon behavior or connection patterns that might indicate exploitation attempts. Additionally, the vulnerability highlights the importance of input validation and memory safety practices in network security software development, emphasizing the need for robust code review processes and automated testing for buffer overflow conditions. Regular security audits of network infrastructure components, particularly those handling untrusted input, should be conducted to identify and remediate similar vulnerabilities before they can be exploited in the wild. The incident also underscores the critical importance of maintaining up-to-date security patches for anonymity networks, as these systems often serve as targets for sophisticated adversaries seeking to compromise privacy protections.