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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
7.5
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVE ID

CVE-2023-38505