Once installed on a Backdoor:OSX/Clientsnow allows a remote attacker to silently perform actions on the infected machine.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.
Backdoor:OSX/Clientsnow appears to have links to the Ghostnet surveillance program allegedly used to spy on prominent activists in the Tibetan and Uyghur communities.
For more information, download the H1 2014 Threat Report.