CVE-2017-18265 in Prosody
Summary
by MITRE
Prosody before 0.10.0 allows remote attackers to cause a denial of service (application crash), related to an incompatibility with certain versions of the LuaSocket library, such as the lua-socket package from Debian stretch. The attacker needs to trigger a stream error. A crash can be observed in, for example, the c2s module.
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Analysis
by VulDB Data Team • 02/03/2020
CVE-2017-18265 represents a denial of service vulnerability affecting Prosody versions prior to 0.10.0, specifically stemming from incompatibilities with certain LuaSocket library versions including the lua-socket package found in Debian stretch. This vulnerability operates through a stream error triggering mechanism that causes application crashes, particularly impacting the c2s module which handles client-to-server connections. The underlying technical flaw arises from improper error handling within Prosody's networking components when processing malformed or unexpected stream data, leading to unhandled exceptions that terminate the application process. The vulnerability is categorized under CWE-400 as an unspecified vulnerability in resource management, specifically manifesting as an unchecked return value error during socket operations. From an operational perspective, this vulnerability presents a significant risk to chat server availability as remote attackers can reliably crash Prosody services by sending specially crafted stream error packets, potentially disrupting communication for all connected users. The attack surface is particularly concerning given that Prosody is widely used for instant messaging and real-time communication services, making this DoS condition a critical threat to service continuity. The vulnerability aligns with ATT&CK technique T1499.004 for network denial of service, specifically targeting application availability through resource exhaustion or process termination. The impact extends beyond simple service disruption as the crash can occur in the c2s module, affecting core server functionality and potentially causing cascading failures in connected services. This vulnerability demonstrates the importance of proper dependency management and thorough testing across different library versions, as the issue was resolved in Prosody 0.10.0 through improved error handling mechanisms and compatibility fixes for the LuaSocket library. Organizations should prioritize updating to patched versions while implementing monitoring for unusual crash patterns and stream error occurrences. The vulnerability also highlights the need for defensive programming practices including proper exception handling, input validation, and robust error recovery mechanisms in networked applications. Security teams should consider implementing rate limiting and connection monitoring as additional mitigations while the primary fix involves upgrading to Prosody 0.10.0 or later versions that contain the necessary compatibility fixes for affected LuaSocket implementations.