Apple Mac OS X OpenSSH nonexistent user login denial of service
| macosx-openssh-nonexistent-user-dos (28147) |  Medium Risk |
Description:
Apple Mac OS X and Mac OS X Server could allow a remote attacker to launch a denial of service attack against the OpenSSH server, if remote login is enabled. When a login is attempted with a username that does not exist, the OpenSSH authentication process will hang. A remote attacker could exploit this vulnerability to determine valid usernames or to prevent legitimate users from accessing the OpenSSH server by flooding the server with invalid login attempts.
*CVSS:
| Base Score: | 4.2 |
| Access Vector: | Remote |
| Access Complexity: | High |
| Authentication: | Not Required |
| Confidentiality Impact: | Partial |
| Integrity Impact: | None |
| Availability Impact: | Partial |
| Temporal Score: | 3.7 |
| Exploitability: | High |
| Remediation Level: | Official-Fix |
| Report Confidence: | Confirmed |
Consequences:
Denial of Service
Remedy:
Apply Apple Security Update 2006-004, available from the Apple Web site. See References.
References:
- Apple Security Update 2006-004: About Security Update 2006-004.
- Apple Security Update 2006-004 for Mac Pro: About Security Update 2006-004 for Mac Pro.
- US-CERT Technical Cyber Security Alert TA06-214A: Apple Mac Products Affected by Multiple Vulnerabilities.
- BID-19289: Apple Mac OS X Multiple Security Vulnerabilities
- CVE-2006-0393: OpenSSH in Apple Mac OS X 10.4.7 allows remote attackers to cause a denial of service or determine account existence by attempting to log in using an invalid user, which causes the server to hang.
- OSVDB ID: 27745: Mac OS X OpenSSH Nonexistent Account Login Enumeration DoS
- SA21253: Mac OS X Security Update Fixes Multiple Vulnerabilities
- SECTRACK ID: 1016672: OpenSSH on Mac OS X Lets Remote Users Deny Service
- VUPEN/ADV-2006-3101: Apple Mac OS X Multiple Remote Code Execution and Local Security Bypass Vulnerabilities
Platforms Affected:
- Apple Mac OS X 10.4.7
- Apple Mac OS X Server 10.4.7
Reported:
Aug 01, 2006
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The information within this database may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. In no event shall IBM be held liable for any damages whatsoever arising out of or in connection with the use or spread of this information.