CVE-2023-1255

Issue summary: The AES-XTS cipher decryption implementation for 64 bit ARM platform contains a bug that could cause it to read past the input buffer, leading to a crash.

Impact summary: Applications that use the AES-XTS algorithm on the 64 bit ARM platform can crash in rare circumstances. The AES-XTS algorithm is usually used for disk encryption.

The AES-XTS cipher decryption implementation for 64 bit ARM platform will read past the end of the ciphertext buffer if the ciphertext size is 4 mod 5 in 16 byte blocks, e.g. 144 bytes or 1024 bytes. If the memory after the ciphertext buffer is unmapped, this will trigger a crash which results in a denial of service.

If an attacker can control the size and location of the ciphertext buffer being decrypted by an application using AES-XTS on 64 bit ARM, the application is affected. This is fairly unlikely making this issue a Low severity one.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=02ac9c9420275868472f33b01def01218742b8bb
• https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=bc2f61ad70971869b242fc1cb445b98bad50074a
• https://security.netapp.com/advisory/ntap-20230908-0006/
• https://www.openssl.org/news/secadv/20230419.txt