Information disclosure in OpenSSL - CVE-2016-7056
Published: January 10, 2017 / Updated: July 5, 2022
Vulnerability identifier: #VU4133
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2016-7056
CWE-ID: CWE-310
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user obtain potentially sensitive information.
The vulnerability exists due the OpenSSL does not properly set the BN_FLG_CONSTTIME for nonces when signing with the P-256 elliptic curve in ecdsa_sign_setup() function in crypto/ec/ecdsa_ossl.c. A local attacker can conduct a cache-timing attack and recover ECDSA P-256 private keys
Successful exploitation of this vulnerability may allow an attacker to obtain potentially sensitive information.
The vulnerability is discovered in OpenSSL 1.0.1u. Other versions may also be affected.
The vulnerability exists due the OpenSSL does not properly set the BN_FLG_CONSTTIME for nonces when signing with the P-256 elliptic curve in ecdsa_sign_setup() function in crypto/ec/ecdsa_ossl.c. A local attacker can conduct a cache-timing attack and recover ECDSA P-256 private keys
Successful exploitation of this vulnerability may allow an attacker to obtain potentially sensitive information.
The vulnerability is discovered in OpenSSL 1.0.1u. Other versions may also be affected.
Affected software
OpenSSL
Fedora
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux Server - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
SUSE Linux
Ubuntu
Opensuse
openssl101e
openssl (Red Hat package)
Fedora
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux Server - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
SUSE Linux
Ubuntu
Opensuse
openssl101e
openssl (Red Hat package)
How to mitigate CVE-2016-7056
Install update from vendor's website.
openssl101e - update to 1.0.1e-10.el5
openssl (Red Hat package) - update to 1.0.2k-8.el7
openssl (Red Hat package) - update to 1.0.2k-8.el7