--version-check behaves like spyware

[Maciej Dobrzanski]

Percona Toolkit 2.1 introduced --version-check to warn user about known vulnerabilities in the local MySQL instance and to check for PT updates. When this option is enabled - and it is enabled by default(!) - various information about local MySQL as well as other system binaries and packages are submitted to Percona along with the server's IP address. This not only exposes possibly sensitive information, but also does so without bringing it to user's attention or asking for their consent.

It gets worse. The configuration for what information PT tools should collect is not hardcoded in the scripts. Instead, every time it's downloaded from http://v.percona.com/. One of the possible parameters is a binary file name to be executed, i.e. Percona can remotely execute arbitrary command - again, without making user aware of what or when is being executed. To be fair, the ability to run commands is limited to running "command -v", however that's only under the assumption that the command filters will always work. The configuration can also ask for any MySQL variable - not just the version string.

In my opinion --version-check should never be enabled by default and if user wants to keep it enabled, the configuration (i.e. the list of checks) should be hardcoded and explicitly listed, and not downloaded from a remote location.

Current workaround: To avoid confidential information being exposed, always use --no-version-check with every PT tool that includes 'version-check' feature (e.g. pt-query-digest, pt-diskstats).

[Alexey Kopytov (akopytov)]

Adding XtraBackup as an affected project. I agree, the decision to enable VersionCheck by default in PXB was dubious. I see no problems in reverting it if many people are unhappy about the current behavior.

[Alexey Kopytov (akopytov)]

See also comments in bug #1255451.

[Daniel Nichter (daniel-nichter)]

Clarification: PT 2.1 --version-check is OFF by default. It's on by default only in 2.2 (and only for certain tools).

[Matt Griffin (mattgriffin)]

@Maciek: Thanks for the report. We're looking into it and will reply soon.

[Seth Arnold (seth-arnold)]

This is CVE-2014-2029; see http://www.openwall.com/lists/oss-security/2014/02/19/14 for details.

Thanks

[Alexey Kopytov (akopytov)]

The command execution part has been reported separately as bug #1285166 and will be fixed in PXB 2.1.8.

[Matt Griffin (mattgriffin)]

@Maciek and @Seth: The fix for this has been released in Percona Toolkit 2.2.7. http://www.mysqlperformanceblog.com/2014/02/25/percona-toolkit-2-2-7-now-available/