CVE-2022-30629: Golang Go Information Disclosure Flaw

CVE-2022-30629 Overview

CVE-2022-30629 is a cryptographic vulnerability in Go's crypto/tls package that affects session ticket handling. The vulnerability stems from non-random values being used for the ticket_age_add field in TLS session tickets. This weakness allows an attacker who can observe TLS handshakes to correlate successive connections by comparing ticket ages during session resumption, potentially enabling user tracking and privacy violations.

Critical Impact

Attackers capable of passive network observation can track users across multiple TLS sessions by correlating predictable ticket age values, compromising user privacy and enabling traffic analysis attacks.

Affected Products

• Golang Go versions prior to 1.17.11
• Golang Go versions 1.18.x prior to 1.18.3

Discovery Timeline

• August 10, 2022 - CVE-2022-30629 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-30629

Vulnerability Analysis

This vulnerability falls under CWE-330 (Use of Insufficiently Random Values). The TLS 1.3 specification requires that the ticket_age_add value in session tickets be generated using a cryptographically secure random number generator. This value is added to the ticket age reported by the client during session resumption to obfuscate the actual ticket age from passive observers.

In affected versions of Go's crypto/tls package, the ticket_age_add values were not sufficiently random. This predictability creates a side channel that allows attackers performing passive network surveillance to correlate TLS connections belonging to the same user. By observing the relationship between reported ticket ages across multiple session resumption attempts, an attacker can determine which connections belong to the same client session ticket, effectively tracking users across sessions.

The attack requires the ability to observe TLS handshakes and some user interaction to trigger session resumption, making exploitation complexity relatively high. However, for adversaries with network-level visibility (such as ISPs, network administrators, or state-level actors), this vulnerability provides a mechanism for tracking encrypted communications without breaking the encryption itself.

Root Cause

The root cause of CVE-2022-30629 is the improper generation of the ticket_age_add field in TLS session tickets within Go's crypto/tls implementation. Instead of using a cryptographically secure random number generator to produce unpredictable values, the affected code produced values with insufficient randomness. This violated the TLS 1.3 specification's requirement for random ticket_age_add values, which exist specifically to prevent the correlation attack this vulnerability enables.

Attack Vector

The attack vector for CVE-2022-30629 is network-based and requires the following conditions:

1. Network Observation: The attacker must be able to passively observe TLS handshakes between the target client and server
2. Session Resumption: The target must perform TLS session resumption using session tickets issued by the vulnerable Go server
3. Multiple Connections: The attacker needs to observe multiple connections to correlate ticket ages

An attacker positioned to observe network traffic (man-in-the-middle position, network tap, or compromised network infrastructure) can collect TLS handshake data. By analyzing the ticket age values across multiple session resumptions, the attacker can identify which connections belong to the same user, enabling user tracking and potentially aiding more sophisticated attacks.

The vulnerability mechanism involves comparing the obfuscated ticket ages reported in session resumption handshakes. Because the obfuscation value (ticket_age_add) is predictable, the actual ticket age can be inferred, allowing connection correlation across sessions.

Detection Methods for CVE-2022-30629

Indicators of Compromise

• Unusual patterns of TLS session analysis or traffic correlation attempts targeting Go-based services
• Evidence of passive network monitoring infrastructure targeting TLS handshakes
• Anomalous interest in session resumption traffic patterns from threat intelligence sources

Detection Strategies

• Audit deployed Go applications and infrastructure to identify versions prior to 1.17.11 or 1.18.3
• Implement software composition analysis (SCA) tools to detect vulnerable Go runtime versions in your environment
• Monitor for reconnaissance activities targeting TLS implementations in your organization
• Review network logs for patterns suggesting traffic correlation attacks

Monitoring Recommendations

• Deploy network detection capabilities to identify unusual TLS handshake analysis patterns
• Implement endpoint monitoring to track Go version deployments across your infrastructure
• Establish alerts for security advisories affecting Go's crypto/tls package
• Monitor for updates from the Go Vulnerability Database for related issues

How to Mitigate CVE-2022-30629

Immediate Actions Required

• Upgrade all Go installations to version 1.17.11 or later (for 1.17.x branch) or 1.18.3 or later (for 1.18.x branch)
• Identify and rebuild all applications compiled with vulnerable Go versions
• Prioritize upgrades for internet-facing services that handle sensitive user sessions
• Review and update container images and build pipelines using affected Go versions

Patch Information

The vulnerability has been addressed in Go versions 1.17.11 and 1.18.3. The fix ensures that ticket_age_add values are generated using a cryptographically secure random number generator, preventing the correlation attack.

Relevant resources:

• Go Dev Change Log - Code change implementing the fix
• Go Dev Issue Tracker - Original issue report
• Go Source Code Commit - Specific commit with the fix
• Golang Announcement Group - Official security announcement

Workarounds

• If immediate upgrading is not possible, consider disabling TLS session tickets temporarily as a mitigation measure
• Implement additional privacy protections at the application layer to reduce the impact of session correlation
• Deploy network segmentation to limit attacker visibility into TLS handshakes
• Consider using a reverse proxy with an updated TLS implementation in front of vulnerable Go applications

# Verify Go version to ensure patched version is installed
go version
# Expected output should show 1.17.11+, 1.18.3+, or a later major version

# Check for vulnerable dependencies in Go modules
go list -m -versions golang.org/x/crypto