CVE-2022-0982 in accel-ppp
Summary
by MITRE • 03/16/2022
The telnet_input_char function in opt/src/accel-pppd/cli/telnet.c suffers from a memory corruption vulnerability, whereby user input cmdline_len is copied into a fixed buffer b->buf without any bound checks. If the server connects with a malicious client, crafted client requests can remotely trigger this vulnerability.
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Analysis
by VulDB Data Team • 03/19/2022
The vulnerability identified as CVE-2022-0982 resides within the telnet_input_char function located in the opt/src/accel-pppd/cli/telnet.c file of a network infrastructure component. This memory corruption flaw represents a classic buffer overflow condition that occurs when user-provided input exceeds the allocated buffer boundaries. The specific technical implementation involves the copying of cmdline_len data into a fixed-size buffer b->buf without implementing any validation or boundary checking mechanisms. This design flaw creates a predictable vector for exploitation where an attacker can craft malicious input that exceeds the buffer capacity, leading to memory corruption that may result in arbitrary code execution or system instability.
The operational impact of this vulnerability extends beyond simple memory corruption to encompass potential remote code execution capabilities within the targeted system. When a malicious client establishes a connection to a server running the vulnerable software, the attacker can submit crafted input sequences that trigger the buffer overflow condition. This scenario aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a direct threat to the integrity and availability of the affected network services. The vulnerability specifically affects systems that utilize the accel-pppd framework for point-to-point protocol access, making it particularly concerning for network infrastructure providers and service operators who rely on such components for user authentication and access control.
The attack surface for CVE-2022-0982 is significant given that telnet protocol implementations are commonly deployed in network infrastructure environments where administrative access is required. This vulnerability can be exploited through the telnet interface, which typically operates over TCP port 23 and is often used for remote system administration. The remote execution aspect of this flaw means that attackers do not require physical access to the target system, making it particularly dangerous in environments where telnet services are exposed to untrusted networks. According to ATT&CK framework reference T1210, this vulnerability could be leveraged for exploitation of remote services, potentially enabling privilege escalation or persistent access to the compromised system. The vulnerability's classification as a buffer overflow directly maps to ATT&CK technique T1059.007, which covers command and scripting interpreter usage, as successful exploitation could allow attackers to execute arbitrary commands through the compromised telnet interface.
Mitigation strategies for CVE-2022-0982 should prioritize immediate patching of the affected software components, as this represents a critical security flaw that could be exploited by remote attackers. Organizations should implement network segmentation to limit access to telnet services, particularly those running vulnerable versions of accel-pppd. The implementation of input validation measures, including length checks and boundary validation, should be enforced in all user input handling functions to prevent similar buffer overflow conditions. Additionally, system administrators should consider disabling telnet services in favor of more secure alternatives such as SSH protocol implementations, which provide encrypted communication channels and better security controls. Regular security audits should include verification of buffer handling practices throughout the codebase, with particular attention to functions that process user input from network sources. The vulnerability's exposure through the telnet protocol interface makes it particularly susceptible to automated scanning and exploitation, emphasizing the need for immediate remediation and monitoring of affected systems.