CVE-2020-35870 in rusqlite Crate
Summary
by MITRE • 12/31/2020
An issue was discovered in the rusqlite crate before 0.23.0 for Rust. Memory safety can be violated via an Auxdata API use-after-free.
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Analysis
by VulDB Data Team • 12/31/2020
The vulnerability resides within the rusqlite crate, a popular rust binding for sqlite database operations, specifically affecting versions prior to 0.23.0. This memory safety issue manifests through the Auxdata API which is used to register auxiliary functions with sqlite databases. The flaw represents a classic use-after-free vulnerability that occurs when memory previously allocated to an object is accessed after it has been deallocated by the system or application logic. Such vulnerabilities are particularly dangerous because they can lead to unpredictable behavior, crashes, or potentially exploitable conditions where attackers might manipulate memory contents to execute arbitrary code.
The technical nature of this flaw stems from improper memory management within the Auxdata API implementation. When auxiliary functions are registered with sqlite through rusqlite, the crate maintains references to these function objects in memory. However, due to inadequate lifecycle management, the memory allocated for these objects can be freed while still being referenced by callback mechanisms within the sqlite engine. This creates a scenario where subsequent calls to these auxiliary functions may attempt to access deallocated memory regions, leading to undefined behavior and potential security implications.
From an operational impact perspective, this vulnerability affects any rust application that utilizes the rusqlite crate with auxiliary data functions, particularly those implementing custom sqlite functions or extensions. The risk level is significant because use-after-free conditions can be exploited by attackers to achieve remote code execution or cause denial of service conditions. Applications handling untrusted input through sqlite queries that utilize auxdata functions are especially vulnerable, as attackers could craft malicious inputs designed to trigger the memory corruption during function execution.
The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations, and can be mapped to ATT&CK technique T1059.007 for execution through command-line interfaces or database functions. Organizations using rusqlite should prioritize immediate patching to version 0.23.0 or later where this memory safety issue has been resolved. Additional mitigations include implementing proper input validation for sqlite queries, avoiding complex auxiliary function usage when possible, and conducting thorough code reviews of database interaction patterns. The fix typically involves ensuring proper reference counting and memory lifecycle management within the crate's internal implementation to prevent premature deallocation of objects referenced by sqlite's callback mechanisms.