CVE-2023-29409: Vulnerability in stdlib package - Slow verification of certificate chains containing large RSA keys
Summary
CVE-2023-29409: Extremely large RSA keys in certificate chains can cause a client/server to expend significant CPU time verifying signatures. Affects golang-1.15 versions < 0ae54ddd37302bdd2a8c775135bf5f076a18eeb3. No fix is published. How to fix ↓
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Background
The stdlib package is a part of the Go programming language's standard library. It provides a collection of essential functions, data types, and utilities that are commonly used in Go programs. The package is widely used in various applications and is considered a fundamental component of the Go ecosystem. However, a vulnerability has been discovered in the package related to the slow verification of certificate chains containing large RSA keys.
Vulnerability Detail
The vulnerability (CVE-2023-29409) in the stdlib package affects the crypto/tls module and specifically impacts the verification of certificate chains containing large RSA keys. When extremely large RSA keys are present in certificate chains, the client/server may consume significant CPU time during the signature verification process. To address this issue, the size of RSA keys transmitted during handshakes has been restricted to a maximum of 8192 bits. This limitation aims to prevent excessive CPU usage and improve the default safety of users of crypto/tls. While there are only three known certificates with keys larger than 8192 bits in circulation, they are test certificates and not actively deployed. It is possible that larger keys are used in private PKIs, but the focus of this fix is on the web PKI.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
There is no specific workaround mentioned for this vulnerability.
Conclusion
The vulnerability in the stdlib package related to the slow verification of certificate chains containing large RSA keys has been addressed in the fixed versions: 1.19.12, 1.20.7, and 1.21.0-rc.4. It is recommended to update the package to mitigate the potential CPU consumption issue during signature verification. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for golang-1.15 →
FAQ
The vulnerability can cause significant CPU usage during the verification of certificate chains containing large RSA keys, potentially leading to performance degradation and resource exhaustion.
No, all known certificates with keys larger than 8192 bits are test certificates and not actively deployed.
While the fix primarily targets the web PKI, it is possible that larger keys are used in private PKIs. However, the impact on private PKIs is expected to be minimal.
The fixed versions of the stdlib package are 1.19.12, 1.20.7, and 1.21.0-rc.4.
No specific workaround has been provided for this vulnerability.
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