CVE-2021-37698: Missing TLS service certificate validation in GelfWriter, ElasticsearchWriter, InfluxdbWriter and Influxdb2Writer
Icinga is a monitoring system which checks the availability of network resources, notifies users of outages, and generates performance data for reporting. In versions 2.5.0 through 2.13.0, ElasticsearchWriter, GelfWriter, InfluxdbWriter and Influxdb2Writer do not verify the server's certificate despite a certificate authority being specified. Icinga 2 instances which connect to any of the mentioned time series databases (TSDBs) using TLS over a spoofable infrastructure should immediately upgrade to version 2.13.1, 2.12.6, or 2.11.11 to patch the issue. Such instances should also change the credentials (if any) used by the TSDB writer feature to authenticate against the TSDB. There are no workarounds aside from upgrading.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
icinga2to a version that resolves this vulnerability.Fixed in 2.11.11 - Upgrade
Upgrade
icinga2to a version that resolves this vulnerability.Fixed in 2.12.6 - Upgrade
Upgrade
icinga2to a version that resolves this vulnerability.Fixed in 2.13.1 - Operational
On affected Icinga 2 instances, change the credentials (if any) used by the TSDB writer feature (ElasticsearchWriter, GelfWriter, InfluxdbWriter, Influxdb2Writer) to authenticate against the TSDB after upgrading.
Event History
Frequently Asked Questions
What is CVE-2021-37698?
CVE-2021-37698 is a vulnerability in Icinga, a monitoring system, which allows an attacker to bypass certificate verification.
How does CVE-2021-37698 affect Icinga?
CVE-2021-37698 affects Icinga versions 2.5.0 through 2.13.0 and allows an attacker to exploit insecure certificate verification.
What is the severity of CVE-2021-37698?
CVE-2021-37698 has a severity score of 7.5, which is considered high.
Which software versions are affected by CVE-2021-37698?
CVE-2021-37698 affects Icinga versions 2.5.0 through 2.13.0 as well as Debian Linux version 9.0.
How can I fix CVE-2021-37698?
To fix CVE-2021-37698, update to Icinga version 2.11.11, 2.12.6, or 2.13.1, or update Debian Linux to a version that is not affected.