TLS data decryption via RSA timing oracle
Published Feb 15, 2023 · Updated Mar 19, 2025
Observable timing discrepancy in GnuTLS 3.7.6 allows remote attackers to recover an RSA-encrypted connection secret over a network. TLS RSA ClientKeyExchange processing takes measurably different times for malformed ciphertexts and ciphertexts with valid PKCS#1 v1.5 padding. Exploitation requires no authentication but requires many crafted messages to a server using TLS RSA key exchange; the recovered secret exposes that connection's application data.
Summary
What happened
Observable timing discrepancy in GnuTLS 3.7.6 allows remote attackers to recover an RSA-encrypted connection secret over a network. TLS RSA ClientKeyExchange processing takes measurably different times for malformed ciphertexts and ciphertexts with valid PKCS#1 v1.5 padding. Exploitation requires no authentication but requires many crafted messages to a server using TLS RSA key exchange; the recovered secret exposes that connection's application data.
The record
- CVE
- CVE-2023-0361
- Published
- Feb 15, 2023
- Updated
- Mar 19, 2025
- Vendor
- GnuTLS Project
- Product
- GnuTLS
- Classifications
- CWE-203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 15, 2023CVE publishedPublication date reported by the CVE source.
- Mar 19, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=gnutls-3.7.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GnuTLS RSA ClientKeyExchange timing testproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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