SB2018120201 - Debian update for openssl
Published: December 2, 2018
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 secuirty vulnerabilities.
1) Improper input validation (CVE-ID: CVE-2018-0732)
The vulnerability allows a remote attacker to cause DoS condition on the target system.
The vulnerability exists due to improper handling of large prime values by the affected software during key agreement operations in a Transport Layer Security (TLS) handshake using an Ephemeral Diffie-Hellman (DHE) based cipher suite. A remote attacker can send a large prime value from a malicious OpenSSL server to a targeted OpenSSL client and cause the client to stop responding while generating a key for the prime value.
2) Information disclosure (CVE-ID: CVE-2018-0734)
The vulnerability allows a local attacker to obtain potentially sensitive information.
The vulnerability exists due to unspecified flaw in Digital Signature Algorithm (DSA). A local attacker can conduct a timing side-channel attack and recover the private key, which could be used to conduct further attacks.
3) Information disclosure (CVE-ID: CVE-2018-0735)
The vulnerability allows a remote attacker to obtain potentially sensitive information.
The vulnerability exists due to disclosure of the OpenSSL ECDSA signature algorithm. A remote attacker can use variations in the signing algorithm to conduct a timing side channel attack and recover the private key.
4) Information disclosure (CVE-ID: CVE-2018-0737)
The vulnerability allows a local attacker to obtain potentially sensitive information on the target system.The weakness exists in the RSA key generation algorithm's BN_mod_inverse() and BN_mod_exp_mont() functions due to a cache timing side channel attack. A local attacker can recover the private key.
5) Side-channel attack (CVE-ID: CVE-2018-5407)
The vulnerability allows a physical attacker to obtain potentially sensitive information.
The vulnerability exists due to due to execution of engine sharing on SMT (e.g.Hyper-Threading) architectures when improper handling of information by the processor. A physical attacker can construct a timing side channel to hijack information from processes that are running in the same core.
Note: the vulnerability has been dubbed as PortSmash microarchitecture bug.
Remediation
Install update from vendor's website.