CVE-2015-8080 in Redis
Summary
by MITRE
Integer overflow in the getnum function in lua_struct.c in Redis 2.8.x before 2.8.24 and 3.0.x before 3.0.6 allows remote attackers to cause a denial of service (memory corruption and application crash) via a large number, which triggers a stack-based buffer overflow.
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Analysis
by VulDB Data Team • 07/24/2022
The vulnerability identified as CVE-2015-8080 represents a critical integer overflow flaw within the Redis database software that affects versions prior to 2.8.24 and 3.0.6. This issue resides in the getnum function located within the lua_struct.c file, demonstrating how seemingly minor code defects can lead to severe system instability. The vulnerability operates by exploiting improper handling of large numeric values during Lua script execution, creating conditions that can result in memory corruption and application crashes.
The technical mechanism behind this vulnerability involves a stack-based buffer overflow that occurs when the getnum function processes exceptionally large numbers. When Redis encounters such values during Lua script interpretation, the integer overflow causes the function to miscalculate buffer boundaries, leading to memory corruption patterns that can be exploited by remote attackers. This flaw falls under the CWE-190 category of Integer Overflow or Wraparound, specifically manifesting as a stack-based buffer overflow that represents a well-documented class of vulnerabilities in systems handling user-provided data.
From an operational perspective, this vulnerability creates significant risk for Redis deployments as it allows remote attackers to execute denial of service attacks without requiring authentication or special privileges. The impact extends beyond simple service disruption, as the memory corruption can potentially lead to application crashes that require manual intervention and system restarts. Organizations running Redis versions affected by this vulnerability face operational challenges including service availability issues, potential data loss during crash recovery, and increased administrative overhead for system maintenance and monitoring.
The attack surface for this vulnerability is particularly concerning given Redis's widespread use in web applications, caching systems, and data processing pipelines where Lua scripting capabilities are commonly employed. Attackers can leverage this flaw by submitting carefully crafted large numeric values through Redis commands, triggering the integer overflow condition that results in system instability. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service, specifically targeting the availability aspect of the CIA triad. Organizations should implement immediate mitigations including updating to patched Redis versions, implementing input validation controls, and monitoring for suspicious numeric value patterns in Redis operations.
The remediation strategy should prioritize immediate deployment of Redis patches for versions 2.8.24 and 3.0.6, while also implementing defensive measures such as input sanitization for numeric values in Lua scripts, rate limiting on script execution, and enhanced monitoring for unusual memory consumption patterns. Security teams should also consider implementing network segmentation and access controls to limit exposure of Redis instances to untrusted networks, reducing the attack surface for exploitation of this and similar vulnerabilities.