OESA-2025-1191

EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications.

Security Fix(es):

Issue summary: A bug has been identified in the processing of key and initialisation vector (IV) lengths. This can lead to potential truncation or overruns during the initialisation of some symmetric ciphers.

Impact summary: A truncation in the IV can result in non-uniqueness, which could result in loss of confidentiality for some cipher modes.

When calling EVPEncryptInitex2(), EVPDecryptInitex2() or EVPCipherInitex2() the provided OSSLPARAM array is processed after the key and IV have been established. Any alterations to the key length, via the "keylen" parameter or the IV length, via the "ivlen" parameter, within the OSSLPARAM array will not take effect as intended, potentially causing truncation or overreading of these values. The following ciphers and cipher modes are impacted: RC2, RC4, RC5, CCM, GCM and OCB.

For the CCM, GCM and OCB cipher modes, truncation of the IV can result in loss of confidentiality. For example, when following NIST's SP 800-38D section 8.2.1 guidance for constructing a deterministic IV for AES in GCM mode, truncation of the counter portion could lead to IV reuse.

Both truncations and overruns of the key and overruns of the IV will produce incorrect results and could, in some cases, trigger a memory exception. However, these issues are not currently assessed as security critical.

Changing the key and/or IV lengths is not considered to be a common operation and the vulnerable API was recently introduced. Furthermore it is likely that application developers will have spotted this problem during testing since decryption would fail unless both peers in the communication were similarly vulnerable. For these reasons we expect the probability of an application being vulnerable to this to be quite low. However if an application is vulnerable then this issue is considered very serious. For these reasons we have assessed this issue as Moderate severity overall.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this because the issue lies outside of the FIPS provider boundary.

OpenSSL 3.1 and 3.0 are vulnerable to this issue.(CVE-2023-5363)

Issue summary: A timing side-channel which could potentially allow recovering the private key exists in the ECDSA signature computation.

Impact summary: A timing side-channel in ECDSA signature computations could allow recovering the private key by an attacker. However, measuring the timing would require either local access to the signing application or a very fast network connection with low latency.

There is a timing signal of around 300 nanoseconds when the top word of the inverted ECDSA nonce value is zero. This can happen with significant probability only for some of the supported elliptic curves. In particular the NIST P-521 curve is affected. To be able to measure this leak, the attacker process must either be located in the same physical computer or must have a very fast network connection with low latency. For that reason the severity of this vulnerability is Low.(CVE-2024-13176)

Issue summary: Calling the OpenSSL API function SSLfreebuffers may cause memory to be accessed that was previously freed in some situations

Impact summary: A use after free can have a range of potential consequences such as the corruption of valid data, crashes or execution of arbitrary code. However, only applications that directly call the SSLfreebuffers function are affected by this issue. Applications that do not call this function are not vulnerable. Our investigations indicate that this function is rarely used by applications.

The SSLfreebuffers function is used to free the internal OpenSSL buffer used when processing an incoming record from the network. The call is only expected to succeed if the buffer is not currently in use. However, two scenarios have been identified where the buffer is freed even when still in use.

The first scenario occurs where a record header has been received from the network and processed by OpenSSL, but the full record body has not yet arrived. In this case calling SSLfreebuffers will succeed even though a record has only been partially processed and the buffer is still in use.

The second scenario occurs where a full record containing application data has been received and processed by OpenSSL but the application has only read part of this data. Again a call to SSLfreebuffers will succeed even though the buffer is still in use.

While these scenarios could occur accidentally during normal operation a malicious attacker could attempt to engineer a stituation where this occurs. We are not aware of this issue being actively exploited.

The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.(CVE-2024-4741)