Source: cna@vuldb.com
A vulnerability was found in rgb2hex up to 0.1.5. It has been rated as problematic. This issue affects some unknown processing. The manipulation leads to inefficient regular expression complexity. The attack may be initiated remotely. Upgrading to version 0.1.6 is able to address this issue. The patch is named 9e0c38594432edfa64136fdf7bb651835e17c34f. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-217151.
rgb2hex versions up to 0.1.5 are vulnerable to a Regular Expression Denial of Service (ReDoS) attack. This vulnerability allows an attacker to cause a significant performance degradation by crafting malicious input, potentially leading to a denial of service and impacting application availability.
Step 1: Input Delivery: The attacker crafts a malicious input string designed to trigger the ReDoS vulnerability in the rgb2hex library. This input likely contains a long string of characters that cause the regex to backtrack extensively.
Step 2: Input Processing: The vulnerable application receives the malicious input and passes it to the rgb2hex library for processing.
Step 3: Regex Execution: The rgb2hex library's regular expression engine attempts to parse the malicious input.
Step 4: Catastrophic Backtracking: Due to the inefficient regex design, the engine enters a state of catastrophic backtracking, exponentially increasing the processing time.
Step 5: Resource Exhaustion: The excessive CPU usage caused by the backtracking leads to resource exhaustion, potentially causing the application or server to become unresponsive or crash.
Step 6: Denial of Service: The application is unable to process legitimate requests, resulting in a denial of service.
The vulnerability lies within the regular expression used by the rgb2hex library to parse and validate color input. Specifically, the regex is susceptible to catastrophic backtracking. By providing a specially crafted input string, an attacker can trigger exponential backtracking within the regex engine. This leads to excessive CPU consumption and a significant slowdown in processing, effectively creating a denial-of-service condition. The root cause is the inefficient design of the regular expression, allowing for an exponential increase in processing time with increasing input complexity. The patch in version 0.1.6 likely refactors the regex to prevent this catastrophic backtracking.
There is no specific APT or malware directly associated with this vulnerability. However, ReDoS attacks are a common technique and could be employed by any attacker. CISA KEV status: Not listed.
Monitor server CPU usage for spikes, especially during periods of high user input or data processing.
Analyze application logs for unusually long processing times related to color conversion or input validation.
Implement network intrusion detection systems (IDS) rules to identify suspicious input patterns that could indicate a ReDoS attack. These rules should look for long strings or patterns that trigger the vulnerable regex.
Monitor application performance metrics for degradation related to the rgb2hex library.
Examine application code for the use of the rgb2hex library and the input validation methods used.
Upgrade the rgb2hex library to version 0.1.6 or later.
Implement input validation to restrict the length and format of user-supplied color input.
Consider using a different color conversion library that is not vulnerable to ReDoS attacks.
Implement rate limiting on requests that utilize the vulnerable library.
Regularly scan dependencies for known vulnerabilities using tools like Snyk or OWASP Dependency-Check.