OpenSSH < 7.0 Multiple Vulnerabilities
High Nessus Plugin ID 85382
SynopsisThe SSH server running on the remote host is affected by multiple vulnerabilities.
DescriptionAccording to its banner, the version of OpenSSH running on the remote host is prior to 7.0. It is, therefore, affected by the following vulnerabilities :
- A security bypass vulnerability exists in the kbdint_next_device() function in file auth2-chall.c that allows the circumvention of MaxAuthTries during keyboard-interactive authentication. A remote attacker can exploit this issue to force the same authentication method to be tried thousands of times in a single pass by using a crafted keyboard-interactive 'devices' string, thus allowing a brute-force attack or causing a denial of service. (CVE-2015-5600)
- A security bypass vulnerability exists in sshd due to improper handling of username data in MONITOR_REQ_PAM_INIT_CTX requests. A local attacker can exploit this, by sending a MONITOR_REQ_PWNAM request, to conduct an impersonation attack. Note that this issue only affects Portable OpenSSH. (CVE-2015-6563)
- A privilege escalation vulnerability exists due to a use-after-free error in sshd that is triggered when handling a MONITOR_REQ_PAM_FREE_CTX request. A local attacker can exploit this to gain elevated privileges.
Note that this issue only affects Portable OpenSSH.
- A local command execution vulnerability exists in sshd due to setting insecure world-writable permissions for TTYs. A local attacker can exploit this, by injecting crafted terminal escape sequences, to execute commands for logged-in users. (CVE-2015-6565)
SolutionUpgrade to OpenSSH 7.0 or later.