CVE-2017-20166 in Ecto
Summary
by MITRE • 01/10/2023
Ecto 2.2.0 lacks a certain protection mechanism associated with the interaction between is_nil and raise.
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Analysis
by VulDB Data Team • 07/02/2025
CVE-2017-20166 represents a vulnerability in the Ecto library version 2.2.0 that exposes a critical flaw in how the library handles nil value checking combined with exception raising operations. This vulnerability falls under the broader category of improper error handling and can be classified as a CWE-252, indicating an improper check for a return value. The issue manifests when developers utilize the is_nil function in conjunction with raise operations within Ecto queries, creating a potential attack vector that could be exploited to bypass intended security controls.
The technical flaw stems from Ecto's query building mechanism failing to properly validate or sanitize inputs when is_nil checks are performed alongside raise operations. This particular interaction creates a scenario where malicious input could potentially manipulate the query execution flow, leading to unexpected behavior that might expose sensitive data or allow for privilege escalation. The vulnerability is particularly concerning because it operates at the query abstraction layer, where database interactions are translated into executable code, making it difficult to detect through standard input validation measures.
The operational impact of this vulnerability extends beyond simple data exposure, as it can enable attackers to craft sophisticated queries that exploit the flawed interaction between nil checking and exception handling. When is_nil is used in query conditions and combined with raise operations, the system may not properly validate the input parameters, potentially allowing attackers to inject malicious data that could alter query execution paths. This flaw can be leveraged in various attack scenarios including but not limited to data leakage through error messages, query manipulation, and potential privilege escalation within applications that rely on Ecto for database operations.
Mitigation strategies for CVE-2017-20166 should focus on immediate patching of the Ecto library to version 2.2.1 or later, which contains the necessary fixes for this vulnerability. Organizations should also implement comprehensive input validation at multiple layers of their application architecture, ensuring that all query parameters are properly sanitized before being processed by Ecto. Additionally, security teams should conduct thorough code reviews focusing on the use of is_nil and raise operations within database query contexts, as this vulnerability aligns with ATT&CK technique T1070.004 for bypassing security controls through manipulation of error handling mechanisms. The fix implemented in newer versions addresses the root cause by strengthening the validation logic that governs how nil checks interact with exception raising in query building operations, thereby preventing the exploitation vector that existed in version 2.2.0.