CVE-2015-4675 in Tiny SRP library
Summary
by MITRE
Buffer overflow in the Tiny SRP library (aka TinySRP) allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via a crafted size value for the username field.
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Analysis
by VulDB Data Team • 05/21/2022
The vulnerability identified as CVE-2015-4675 represents a critical buffer overflow flaw within the Tiny SRP library, a lightweight implementation of the Secure Remote Password protocol designed for authentication purposes. This library is commonly integrated into embedded systems, IoT devices, and network appliances where minimal resource usage is essential for operation. The vulnerability specifically manifests when processing authentication requests containing maliciously crafted username fields that exceed expected buffer boundaries. The flaw stems from inadequate input validation mechanisms that fail to properly sanitize or limit the size of user-provided data before processing. According to the Common Weakness Enumeration catalog, this vulnerability maps to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The security implications extend beyond simple denial of service, as the buffer overflow can potentially be exploited to execute arbitrary code within the context of the vulnerable application.
The technical exploitation of this vulnerability requires an attacker to craft a specially formatted authentication request with an oversized username field that exceeds the allocated buffer space within the TinySRP library implementation. When the library processes this malformed input, the excessive data overflows into adjacent memory regions, potentially corrupting critical program state information, function return addresses, or other sensitive data structures. The attack vector is remote, meaning that adversaries can trigger this vulnerability without physical access to the target system, making it particularly dangerous for networked devices and services that rely on TinySRP for authentication. The vulnerability's impact is compounded by the fact that the affected library is often embedded within critical infrastructure components, including routers, switches, and security appliances where authentication failures can lead to complete system compromise. This aligns with the attack pattern described in the MITRE ATT&CK framework under the technique of 'Exploitation for Privilege Escalation' and 'Remote Code Execution' within the context of network infrastructure targets.
The operational impact of CVE-2015-4675 extends beyond immediate service disruption to potentially enable full system compromise and persistent access within affected networks. Organizations utilizing vulnerable implementations may experience unexpected system crashes, authentication failures, or in more severe cases, complete system takeover by malicious actors who successfully exploit the buffer overflow to inject and execute malicious code. The vulnerability affects a wide range of network appliances and embedded systems that rely on TinySRP for secure authentication, including but not limited to wireless access points, network security devices, and industrial control systems. The complexity of the attack surface increases when considering that many of these devices operate in environments where patching and updates are infrequent or impossible due to operational constraints, making the vulnerability particularly persistent. Organizations should conduct comprehensive vulnerability assessments across their infrastructure to identify all instances of the TinySRP library implementation and implement immediate mitigations to prevent exploitation attempts that could lead to unauthorized access or system compromise.