diff --git a/lib/private/DB/ConnectionFactory.php b/lib/private/DB/ConnectionFactory.php
index c841a36bb5..9fc2ed42c3 100644
--- a/lib/private/DB/ConnectionFactory.php
+++ b/lib/private/DB/ConnectionFactory.php
@@ -193,16 +193,7 @@ class ConnectionFactory {
 			$connectionParams['path'] = $dataDir . '/' . $name . '.db';
 		} else {
 			$host = $this->config->getValue('dbhost', '');
-			if (strpos($host, ':')) {
-				// Host variable may carry a port or socket.
-				list($host, $portOrSocket) = explode(':', $host, 2);
-				if (ctype_digit($portOrSocket)) {
-					$connectionParams['port'] = $portOrSocket;
-				} else {
-					$connectionParams['unix_socket'] = $portOrSocket;
-				}
-			}
-			$connectionParams['host'] = $host;
+			$connectionParams = array_merge($connectionParams, $this->splitHostFromPortAndSocket($host));
 			$connectionParams['dbname'] = $name;
 		}
 
@@ -232,4 +223,27 @@ class ConnectionFactory {
 
 		return $connectionParams;
 	}
+
+	/**
+	 * @param string $host
+	 * @return array
+	 */
+	protected function splitHostFromPortAndSocket($host): array {
+		$params = [
+			'host' => $host,
+		];
+
+		$matches = [];
+		if (preg_match('/^(.*):([^\]:]+)$/', $host, $matches)) {
+			// Host variable carries a port or socket.
+			$params['host'] = $matches[1];
+			if (is_numeric($matches[2])) {
+				$params['port'] = (int) $matches[2];
+			} else {
+				$params['unix_socket'] = $matches[2];
+			}
+		}
+
+		return $params;
+	}
 }
diff --git a/tests/lib/DB/ConnectionFactoryTest.php b/tests/lib/DB/ConnectionFactoryTest.php
new file mode 100644
index 0000000000..6a1a9b31c4
--- /dev/null
+++ b/tests/lib/DB/ConnectionFactoryTest.php
@@ -0,0 +1,56 @@
+<?php
+/**
+ * @copyright Copyright (c) 2018 Joas Schilling <coding@schilljs.com>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace Test\DB;
+
+use OC\DB\ConnectionFactory;
+use OC\SystemConfig;
+use Test\TestCase;
+
+class ConnectionFactoryTest extends TestCase {
+
+	public function splitHostFromPortAndSocketData() {
+		return [
+			['127.0.0.1', ['host' => '127.0.0.1']],
+			['db.example.org', ['host' => 'db.example.org']],
+			['unix', ['host' => 'unix']],
+			['[::1]', ['host' => '[::1]']],
+			['127.0.0.1:3306', ['host' => '127.0.0.1', 'port' => 3306]],
+			['db.example.org:3306', ['host' => 'db.example.org', 'port' => 3306]],
+			['unix:3306', ['host' => 'unix', 'port' => 3306]],
+			['[::1]:3306', ['host' => '[::1]', 'port' => 3306]],
+			['unix:/socket', ['host' => 'unix', 'unix_socket' => '/socket']],
+		];
+	}
+
+	/**
+	 * @dataProvider splitHostFromPortAndSocketData
+	 * @param string $host
+	 * @param array $expected
+	 */
+	public function testSplitHostFromPortAndSocket($host, array $expected) {
+		/** @var SystemConfig $config */
+		$config = $this->createMock(SystemConfig::class);
+		$factory = new ConnectionFactory($config);
+
+		$this->assertEquals($expected, self::invokePrivate($factory, 'splitHostFromPortAndSocket', [$host]));
+	}
+}