CVE-2020-15113

In etcd before versions 3.3.23 and 3.4.10, certain directory paths are created (etcd data directory and the directory path when provided to automatically generate self-signed certificates for TLS connections with clients) with restricted access permissions (700) by using the os.MkdirAll. This function does not perform any permission checks when a given directory path exists already. A possible workaround is to ensure the directories have the desired permission (700).

Vulnerability type

Access Controls

Detail

etcd creates certain directory paths (etcd data directory and the directory path when provided to automatically generate self-signed certificates for TLS connections with clients) with restricted access permissions (700) by using the os.MkdirAll. This function does not perform any permission checks when a given directory path exists already.

Specific Go Package Affected

github.com/etcd-io/etcd/pkg/fileutil

Workarounds

Make sure these directories have the desired permit (700).

References

Find out more on this vulnerability in the security audit report

For more information

If you have any questions or comments about this advisory:

• Contact the etcd security committee

In etcd before versions 3.3.23 and 3.4.10, certain directory paths are created (etcd data directory and the directory path when provided to automatically generate self-signed certificates for TLS connections with clients) with restricted access permissions (700) by using the os.MkdirAll. This function does not perform any permission checks when a given directory path exists already. A possible workaround is to ensure the directories have the desired permission (700).

In etcd before versions 3.3.23 and 3.4.10, certain directory paths are created (etcd data directory and the directory path when provided to automatically generate self-signed certificates for TLS connections with clients) with restricted access permissions (700) by using the os.MkdirAll. This function does not perform any permission checks when a given directory path exists already. A possible workaround is to ensure the directories have the desired permission (700).

It was discovered that etcd incorrectly handled certain specially crafted WAL files. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-15106, CVE-2020-15112)

It was discovered that etcd incorrectly handled directory permissions when trying to create a directory that exists already. An attacker could possibly use this issue to obtain sensitive information. (CVE-2020-15113)

It was discovered that etcd incorrectly handled endpoint setup. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-15114)

USN-5628-1 fixed vulnerabilities in etcd. This update provides the corresponding updates for Ubuntu 18.04 ESM.

Original advisory details:

It was discovered that etcd incorrectly handled certain specially crafted WAL files. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-15106, CVE-2020-15112)

It was discovered that etcd incorrectly handled directory permissions when trying to create a directory that exists already. An attacker could possibly use this issue to obtain sensitive information. (CVE-2020-15113)

It was discovered that etcd incorrectly handled endpoint setup. An attacker could possibly use this issue to cause a denial of service. (CVE-2020-15114)