SB2018090704 - Amazon Linux AMI update for krb5
Published: September 7, 2018
Security Bulletin ID
SB2018090704
CSH Severity
High
Patch available
YES
Number of vulnerabilities
2
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Denial of service (CVE-ID: CVE-2017-11368)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote authenticated attacker to cause DoS condition on the target system.
The weakness exists due to an assertion failure. A remote attacker can send invalid S4U2Self or S4U2Proxy requests and cause the krb5kdc service to exit on a targeted system.
Successful exploitation of the vulnerability results in denial of service.
2) Authentication bypass (CVE-ID: CVE-2017-7562)
CWE-ID: CWE-592 - Authentication Bypass Issues
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote authenticated attacker to write arbitrary files on the target system.
The weakness exists due to an authentication bypass in the way krb5's certauth interface handled the validation of client certificates. A remote attacker can impersonate arbitrary principals under rare and erroneous circumstances.
Remediation
Install update from vendor's website.