CVE-2023-41056: Heap Overflow Vulnerability in Redis In-Memory Database

Overview

Redis, a renowned in-memory database storing keys and values, has a severe vulnerability, identified as CVE-2023-41056. This flaw originates from the incorrect handling of memory buffer resizing, which can result in an integer overflow, leading to a heap overflow. The vulnerability is of significant concern as it could potentially lead to remote code execution, posing a serious threat to the integrity and security of systems running affected versions of Redis. This can result in systemic compromise or data leakage, making it a potentially catastrophic issue for organizations that depend on Redis for their operations.

Vulnerability Summary

CVE ID: CVE-2023-41056
Severity: High (8.1 CVSS Score)
Attack Vector: Network
Privileges Required: Low
User Interaction: None
Impact: System compromise, data leakage

Affected Products

Product | Affected Versions

Redis | Below 7.0.15
Redis | Below 7.2.4

How the Exploit Works

The exploit targets the memory buffer resizing mechanism within Redis. When an attacker sends a specifically crafted input to the Redis server, it triggers an integer overflow during the resizing process. This overflow then leads to a heap overflow, a memory corruption issue that can grant the attacker the ability to execute arbitrary code on the affected system. Depending on the level of privileges associated with the Redis service, this could potentially lead to full system compromise.

Conceptual Example Code

Here is a conceptual example of how an attacker might exploit this vulnerability, using a malicious payload sent to the Redis server:

POST /redis/command HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "command": "SET key $(python -c 'print("A"*1000000000)')" }

The above code is a simplified illustration. In practice, the attacker would craft a complex payload designed to trigger the integer overflow and subsequent heap overflow, potentially leading to remote code execution.

Mitigation Guidance

Users are strongly advised to update their Redis instances to versions 7.0.15 or 7.2.4, which includes patches for this vulnerability. For those unable to update immediately, a web application firewall (WAF) or intrusion detection system (IDS) can be utilized as temporary mitigation to monitor and block potential exploit attempts.