CVE-2023-24536 Explained : Impact and Mitigation

This CVE involves excessive resource consumption in

net/http

,

net/textproto

, and

mime/multipart

, which can lead to a denial of service attack due to high CPU and memory usage when processing form inputs with a large number of parts.

Understanding CVE-2023-24536

This vulnerability arises from issues in form parsing that can result in significant CPU and memory consumption, potentially leading to a denial of service attack.

What is CVE-2023-24536?

The vulnerability in

mime/multipart

can allow an attacker to exploit a program that parses multipart forms, causing it to consume excessive CPU and memory resources. It impacts programs using

mime/multipart.Reader.ReadForm

, as well as form parsing in the

net/http

package with various Request methods.

The Impact of CVE-2023-24536

The impact of this vulnerability is the potential for a denial of service attack where an attacker can cause a program to consume large amounts of CPU and memory by manipulating multipart form inputs.

Technical Details of CVE-2023-24536

This section provides more detailed information on the vulnerability, affected systems, and how the exploitation mechanism works.

Vulnerability Description

The issue originates in

mime/multipart.Reader.ReadForm

, which can undercount memory consumption, leading to unanticipated larger inputs and increased pressure on the garbage collector. This can be exploited to overload CPU and memory resources.

Affected Systems and Versions

The vulnerability affects the

Go standard library

versions less than

1.19.8

for

mime/multipart

and

net/textproto

. Specifically, versions between

1.20.0-0

and less than

1.20.3

are impacted.

Exploitation Mechanism

Attackers can exploit the vulnerability by submitting form inputs containing a large number of parts, which can trigger excessive CPU and memory consumption when the program parses the multipart form.

Mitigation and Prevention

To address CVE-2023-24536, immediate actions should be taken to mitigate the risk and prevent potential attacks.

Immediate Steps to Take

Update affected systems to versions that include the fix for

mime/multipart

and

net/textproto

.
Implement restrictions on form inputs to prevent the submission of a large number of parts.
Monitor system resources for unusual consumption that may indicate an attack.

Long-Term Security Practices

Regularly update and patch software to ensure the latest security fixes are in place.
Conduct security audits to identify and address vulnerabilities in code.
Implement rate limiting and resource allocation policies to prevent resource exhaustion attacks.

Patching and Updates

Ensure that systems are updated to versions

1.19.8

or later for

mime/multipart

and

net/textproto

to mitigate the impact of CVE-2023-24536. Additionally, consider adjusting environment variables to set limits on form parts and header fields to enhance security.