CVE-2015-20111 in Bitcoin
Summary
by MITRE • 11/18/2024
miniupnp before 4c90b87, as used in Bitcoin Core before 0.12 and other products, lacks checks for snprintf return values, leading to a buffer overflow and significant data leak, a different vulnerability than CVE-2019-12107. In Bitcoin Core before 0.12, remote code execution was possible in conjunction with CVE-2015-6031 exploitation.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 11/18/2024
The vulnerability identified as CVE-2015-20111 represents a critical buffer overflow flaw in the miniupnp library implementation that affected Bitcoin Core versions prior to 0.12 and numerous other software products. This vulnerability stems from inadequate error checking mechanisms within the snprintf function calls, which are fundamental to safe string manipulation in C-based applications. The absence of proper return value validation creates a scenario where buffer overflows can occur when handling network input data, potentially leading to memory corruption and unauthorized data exposure. The flaw specifically manifests when the miniupnp library processes incoming UPnP (Universal Plug and Play) messages, which are commonly used for network port mapping and device discovery in home networking environments. This vulnerability is distinct from CVE-2019-12107, indicating that it represents a separate class of buffer overflow issues within the same codebase. The technical implementation of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory regions. From an operational perspective, this vulnerability exposes systems to significant security risks including potential data leaks, system instability, and unauthorized access to network resources. The impact extends beyond simple information disclosure, as demonstrated by the combination with CVE-2015-6031, which enabled remote code execution capabilities when exploited together. This combination of vulnerabilities creates a particularly dangerous attack vector that allows adversaries to gain full control over affected systems through carefully crafted network packets. The exploitation of this vulnerability requires network access to the affected service and typically involves sending malformed UPnP messages that trigger the buffer overflow condition. The flaw affects not only Bitcoin Core but also numerous other applications that rely on miniupnp for network functionality, making it a widespread concern across multiple software ecosystems. The vulnerability's presence in network services that handle external input makes it particularly attractive to attackers seeking to compromise systems without requiring physical access or prior authentication. Security researchers have classified this issue as a high-severity vulnerability due to its potential for both data leakage and remote code execution when combined with other exploits. The root cause analysis reveals that the vulnerability exists in the library's handling of string formatting operations where the return values from snprintf functions are not properly validated, leading to situations where the buffer size calculations fail to account for actual string lengths. The ATT&CK framework categorizes this vulnerability under T1059.007 for command and scripting interpreter usage, as the potential for remote code execution enables attackers to execute arbitrary commands on affected systems. Organizations implementing affected software must consider both immediate patching strategies and broader network security measures to protect against exploitation attempts. The vulnerability demonstrates the critical importance of input validation and proper error handling in network-facing applications, particularly those handling untrusted data from external sources. Proper mitigation requires updating to patched versions of miniupnp and Bitcoin Core, implementing network segmentation to limit exposure, and conducting thorough vulnerability assessments to identify other potential instances of similar flaws in the software ecosystem.