CVE-2020-35892

Step 1: Target Identification: The attacker identifies systems or applications that utilize the simple-slab crate, specifically versions prior to 0.3.3.

Step 2: Input Manipulation: The attacker crafts a malicious input that triggers the index() function with an out-of-bounds index value.

Step 3: Vulnerability Trigger: The crafted input is processed by the vulnerable code, leading to an attempt to read from memory outside the allocated bounds.

Step 4: Information Disclosure: The out-of-bounds read occurs, potentially exposing sensitive data residing in adjacent memory locations.

Step 5: Data Exfiltration (Optional): The attacker may attempt to exfiltrate the disclosed data or leverage it to further compromise the system, depending on the nature of the exposed information.

The vulnerability lies within the index() function of the simple-slab crate. The root cause is an insufficient bounds check when accessing memory within the slab allocator. Specifically, the code fails to properly validate the provided index before attempting to read from the underlying memory buffer. This allows an attacker to supply an index value outside the allocated memory region, leading to an out-of-bounds read. This read can expose sensitive data stored in adjacent memory locations, potentially including secrets, credentials, or other confidential information. The severity is amplified if the read data is subsequently used in a way that allows for further exploitation, such as influencing program control flow or triggering other vulnerabilities. The lack of proper bounds checking constitutes a logic error that can be exploited for information disclosure.