diff --git a/src/Composer/Installer/LibraryInstaller.php b/src/Composer/Installer/LibraryInstaller.php
index db2fe535b..0873ed63c 100644
--- a/src/Composer/Installer/LibraryInstaller.php
+++ b/src/Composer/Installer/LibraryInstaller.php
@@ -147,6 +147,12 @@ class LibraryInstaller implements InstallerInterface
         foreach ($package->getBinaries() as $bin) {
             $link = $this->binDir.'/'.basename($bin);
             if (file_exists($link)) {
+                if (is_link($link)) {
+                    // likely leftover from a previous install, make sure
+                    // that the target is still executable in case this
+                    // is a fresh install of the vendor.
+                    chmod($link, 0755);
+                }
                 $this->io->write('Skipped installation of '.$bin.' for package '.$package->getName().', name conflicts with an existing file');
                 continue;
             }
@@ -156,14 +162,14 @@ class LibraryInstaller implements InstallerInterface
                 // add unixy support for cygwin and similar environments
                 if ('.bat' !== substr($bin, -4)) {
                     file_put_contents($link, $this->generateUnixyProxyCode($bin, $link));
-                    chmod($link, 0777);
+                    chmod($link, 0755);
                     $link .= '.bat';
                 }
                 file_put_contents($link, $this->generateWindowsProxyCode($bin, $link));
             } else {
                 symlink($bin, $link);
             }
-            chmod($link, 0777);
+            chmod($link, 0755);
         }
     }