{"vuid":"VU#797027","idnumber":"797027","name":"OpenSSH does not initialize PAM session thereby allowing PAM restrictions to be bypassed","keywords":["OpenSSH","PAM","rsh","pty","rlimits","bypass restrictions","user authentication","user input","session initialization","interactive","non-interactive"],"overview":"OpenSSH is an implementation of the Secure Shell (SSH) protocol. It can be configured to use Linux Pluggable Authentication Modules (PAM) for added authentication. A vulnerability exists in OpenSSH, and perhaps other implementations of SSH, which can allow to potentially bypass PAM restrictions.","clean_desc":"OpenSSH fails to call pam_open_session if no pty (pseudo-terminal driver) is used. This in turn does not activate the security modules specified in /etc/pam.d. It has been pointed out that if you use pam_limits.so to set resource limits, then users could bypass these limits by calling ssh in this manner.","impact":"An attacker can bypass the PAM security modules specified on the target machine.","resolution":"Upgrade to OpenSSH 2.9.9p1.","workarounds":"Restrict access to the SSH service You may wish to disable the SSH access until a patch is available from your vendor. If you cannot disable the service, you can limit your exposure to these vulnerabilities by using a router or firewall to restrict access to port 22/TCP (SSH). Implement a TCPWRAPPER.","sysaffected":"","thanks":"Christian Kraemer discovered this vulnerability.","author":"This document was written by Jason Rafail.","public":["http://www.securityfocus.com/bid/2917","http://archives.neohapsis.com/archives/bugtraq/2001-06/0303.html","http://marc.theaimsgroup.com/?l=bugtraq&m=99324968918628&w=2"],"cveids":[""],"certadvisory":"","uscerttechnicalalert":null,"datecreated":"2001-06-29T17:25:21Z","publicdate":"2001-06-19T00:00:00Z","datefirstpublished":"2001-12-07T23:19:25Z","dateupdated":"2001-12-12T14:39:58Z","revision":5,"vrda_d1_directreport":"","vrda_d1_population":"","vrda_d1_impact":"","cam_widelyknown":"20","cam_exploitation":"0","cam_internetinfrastructure":"5","cam_population":"12","cam_impact":"3","cam_easeofexploitation":"20","cam_attackeraccessrequired":"10","cam_scorecurrent":"3.375","cam_scorecurrentwidelyknown":"3.375","cam_scorecurrentwidelyknownexploited":"6.075","ipprotocol":"","cvss_accessvector":"","cvss_accesscomplexity":"","cvss_authentication":null,"cvss_confidentialityimpact":"","cvss_integrityimpact":"","cvss_availabilityimpact":"","cvss_exploitablity":null,"cvss_remediationlevel":"","cvss_reportconfidence":"","cvss_collateraldamagepotential":"","cvss_targetdistribution":"","cvss_securityrequirementscr":"","cvss_securityrequirementsir":"","cvss_securityrequirementsar":"","cvss_basescore":"","cvss_basevector":"","cvss_temporalscore":"","cvss_environmentalscore":"","cvss_environmentalvector":"","metric":3.375,"vulnote":null}