Buffer Overflow Affecting openssl-src package, versions <111.16.0+1.1.1l
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RUST-OPENSSLSRC-1569485
- published25 Aug 2021
- disclosed24 Aug 2021
- creditUnknown
Introduced: 24 Aug 2021
CVE-2021-3711 (opens in a new tab)How to fix?
Upgrade openssl-src to version 111.16.0+1.1.1l or higher.
Overview
openssl-src is a crate that contains the logic to build OpenSSL and is intended to be consumed by the openssl-sys crate.
Affected versions of this package are vulnerable to Buffer Overflow. In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt(). Typically an application will call this function twice. The first time, on entry, the out parameter can be NULL and, on exit, the outlen parameter is populated with the buffer size required to hold the decrypted plaintext. The application can then allocate a sufficiently sized buffer and call EVP_PKEY_decrypt() again, but this time passing a non-NULL value for the "out" parameter.
A bug in the implementation of the SM2 decryption code means that the calculation of the buffer size required to hold the plaintext returned by the first call to EVP_PKEY_decrypt() can be smaller than the actual size required by the second call. This can lead to a buffer overflow when EVP_PKEY_decrypt() is called by the application a second time with a buffer that is too small.
A malicious attacker who is able present SM2 content for decryption to an application could cause attacker chosen data to overflow the buffer by up to a maximum of 62 bytes altering the contents of other data held after the buffer, possibly changing application behaviour or causing the application to crash. The location of the buffer is application dependent but is typically heap allocated.