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Insufficient TLS Handshake Pool leading to Denial of Service

High
ravenclaw900 published GHSA-3jr4-9rxf-fr44 Jul 26, 2023

Package

cargo dietpi-dashboard (Rust)

Affected versions

0.6.1

Patched versions

0.6.2

Description

Summary

The dashboard only allows for one TLS handshake to be in process at a given moment. Once a TCP connection is established in HTTPS mode, it will assume that it should be waiting for a handshake, and will stay this way indefinitely until a handshake starts or some error occurs. This can be exploited by simply not starting the handshake, preventing any other TLS handshakes from getting through.

Impact

An attacker can lock the dashboard in a state where it is waiting for a TLS handshake from the attacker, who won't provide it. This prevents any legitimate traffic from getting to the dashboard, and can last indefinitely.

Patches

Version 0.6.2 fixes this issue with a more robust TLS handshake system that can handle multiple handshakes at once and will timeout a handshake after 10 seconds.

Workarounds

Do not use HTTPS mode on the open internet where anyone can connect. Instead, put a reverse proxy in front of the dashboard, and have it handle any HTTPS connections. Upgrade to 0.6.2.

References

Demonstration of attack: https://asciinema.org/a/8nRKbdf7AkPLmP3QxFZUSmPwp?t=7

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE ID

CVE-2023-38505