CVE-2021-3711 in OpenSSL can allow to change an application’s behavior
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2021-3711 +1 in the same advisory: …3712 | In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt(). 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. Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k). NVD description · AI analysis pending | 9.8 group max | 88% |
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Full article256 words · extracted from securityaffairs.com · click to collapse
The OpenSSL Project patched a high-severity vulnerability, tracked as CVE-2021-3711, that can allow an attacker to change an application’s behavior or cause the app to crash.
The OpenSSL Project released the OpenSSL 1.1.1l version that addresses a high-severity buffer overflow flaw, tracked as CVE-2021-3711, that could allow an attacker to change an application’s behavior or cause the app to crash.
The vulnerability ties the decryption of SM2 encrypted data, the changes depend on the targeted application and data it maintains (i.e. credentials) in the heap while the issue is exploited.
“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. Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k).” reads the description for this flaw.
The flaw affects versions prior 1.1.1, it was discovered by John Ouyang.
OpenSSL Project also fixed a medium-severity vulnerability, tracked as CVE-2021-3712, that can be exploited by attackers to trigger a denial-of-service (DoS) condition. The flaw could also result in the disclosure of private memory contents (such as private keys, or sensitive plaintext). The vulnerability affects versions 1.1.1-1.1.1k and was fixed in OpenSSL 1.1.1j and 1.0.2za.
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