CVE-2024-5535 — SSL_select_next_proto buffer overread

Affected: OpenSSL, Siemens RUGGEDCOM RST2428P, Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family, Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family, Siemens SIDIS Prime, Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Issue summary: Calling the OpenSSL API function SSL_select_next_proto with an empty supported client protocols buffer may cause a crash or memory contents to be sent to the peer.

Impact summary: A buffer overread can have a range of potential consequences such as unexpected application beahviour or a crash. In particular this issue could result in up to 255 bytes of arbitrary private data from memory being sent to the peer leading to a loss of confidentiality. However, only applications that directly call the SSL_select_next_proto function with a 0 length list of supported client protocols are affected by this issue. This would normally never be a valid scenario and is typically not under attacker control but may occur by accident in the case of a configuration or programming error in the calling application.

The OpenSSL API function SSL_select_next_proto is typically used by TLS applications that support ALPN (Application Layer Protocol Negotiation) or NPN (Next Protocol Negotiation). NPN is older, was never standardised and is deprecated in favour of ALPN. We believe that ALPN is significantly more widely deployed than NPN. The SSL_select_next_proto function accepts a list of protocols from the server and a list of protocols from the client and returns the first protocol that appears in the server list that also appears in the client list. In the case of no overlap between the two lists it returns the first item in the client list. In either case it will signal whether a…

USN-6937-1 — openssl vulnerabilities

Affected: Ubuntu:20.04:LTS: openssl, Ubuntu:22.04:LTS: openssl, Ubuntu:24.04:LTS: openssl

It was discovered that OpenSSL incorrectly handled TLSv1.3 sessions when certain non-default TLS server configurations were in use. A remote attacker could possibly use this issue to cause OpenSSL to consume resources, leading to a denial of service. (CVE-2024-2511)

It was discovered that OpenSSL incorrectly handled checking excessively long DSA keys or parameters. A remote attacker could possibly use this issue to cause OpenSSL to consume resources, leading to a denial of service. This issue only affected Ubuntu 22.04 LTS and Ubuntu 24.04 LTS. (CVE-2024-4603)

William Ahern discovered that OpenSSL incorrectly handled certain memory operations in a rarely-used API. A remote attacker could use this issue to cause OpenSSL to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2024-4741)

Joseph Birr-Pixton discovered that OpenSSL incorrectly handled calling a certain API with an empty supported client protocols buffer. A remote attacker could possibly use this issue to obtain sensitive information, or cause OpenSSL to crash, resulting in a denial of service. (CVE-2024-5535)

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CVE-2024-5535 — SSL_select_next_proto buffer overread

USN-6937-1 — openssl vulnerabilities