diff --git a/launch/src/main/scala/xsbt/boot/Update.scala b/launch/src/main/scala/xsbt/boot/Update.scala
index e4dd34cc7..5c8492cae 100644
--- a/launch/src/main/scala/xsbt/boot/Update.scala
+++ b/launch/src/main/scala/xsbt/boot/Update.scala
@@ -393,18 +393,20 @@ final class Update(config: UpdateConfiguration) {
     }
 }
 
-import SbtIvyLogger.{ acceptError, acceptMessage }
+import SbtIvyLogger.{ acceptError, acceptMessage, isAlwaysIgnoreMessage }
 
 /**
  * A custom logger for Ivy to ignore the messages about not finding classes
  * intentionally filtered using proguard and about 'unknown resolver'.
  */
 private final class SbtIvyLogger(logWriter: PrintWriter) extends DefaultMessageLogger(Message.MSG_INFO) {
-  override def log(msg: String, level: Int) {
-    logWriter.println(msg)
-    if (level <= getLevel && acceptMessage(msg))
-      System.out.println(msg)
-  }
+  override def log(msg: String, level: Int): Unit =
+    if (isAlwaysIgnoreMessage(msg)) ()
+    else {
+      logWriter.println(msg)
+      if (level <= getLevel && acceptMessage(msg))
+        System.out.println(msg)
+    }
   override def rawlog(msg: String, level: Int) { log(msg, level) }
   /** This is a hack to filter error messages about 'unknown resolver ...'. */
   override def error(msg: String) = if (acceptError(msg)) super.error(msg)
@@ -418,4 +420,7 @@ private object SbtIvyLogger {
   val UnknownResolver = "unknown resolver"
   def acceptError(msg: String) = acceptMessage(msg) && !msg.startsWith(UnknownResolver)
   def acceptMessage(msg: String) = (msg ne null) && !msg.startsWith(IgnorePrefix)
+  def isAlwaysIgnoreMessage(msg: String): Boolean =
+    (msg eq null) ||
+      (msg startsWith "setting 'http.proxyPassword'")
 }
diff --git a/notes/0.13.6.md b/notes/0.13.6.md
index 1ddc94e59..92871dc15 100644
--- a/notes/0.13.6.md
+++ b/notes/0.13.6.md
@@ -1,5 +1,6 @@
   [413]: https://github.com/sbt/sbt/issues/413
   [528]: https://github.com/sbt/sbt/issues/528
+  [670]: https://github.com/sbt/sbt/issues/670
   [856]: https://github.com/sbt/sbt/issues/856
   [1036]: https://github.com/sbt/sbt/pull/1036
   [1059]: https://github.com/sbt/sbt/issues/1059
@@ -107,6 +108,7 @@
 - set no longer removes any `++` scala version setting.  [#856][856]/[#1489][1489] by [@jsuereth][@jsuereth]
 - Fixes `Scope.parseScopedKey`. [#1384][1384] by [@eed3si9n][@eed3si9n]
 - Fixes `build.sbt` errors causing `ArrayIndexOutOfBoundsException` due to invalid source in position. [#1181][1181] by [@eed3si9n][@eed3si9n]
+- Fixes `http.proxyPassword` showing up in launcher's update.log. [#670][670] by [@eed3si9n][@eed3si9n]
 - Fixes config-classes leak in loading build files. [#1524][1524] by [@jsuereth][@jsuereth]
 - Fixes name-conflicts in hashed settings class files. [#1465][1465] by [@jsuereth][@jsuereth]
 - Fixes `NullPointerError` in tab completion by `FileExamples`. [#1530][1530] by [@eed3si9n][@eed3si9n]