The Democratic National Committee said Thursday that a thwarted attempt to hack into its voter database was actually a test built by a third party.

On Wednesday, the DNC said it contacted law enforcement after detecting a suspected cyberattack on Tuesday. The party added that it stopped the hacking attempt, and attackers did not modify voter data.

In a statement, DNC Chief Security Officer Bob Lord said the test “mimicked several attributes of actual attacks” on the party’s voter database, VoteBuilder. However, he said neither the DNC nor VoteBuilder or any of the party’s security vendors authorized the test.