diff --git a/scripts/release/upload-dist-lftp.sh b/scripts/release/upload-dist-lftp.sh
index 83a96644..80ff85a8 100644
--- a/scripts/release/upload-dist-lftp.sh
+++ b/scripts/release/upload-dist-lftp.sh
@@ -23,20 +23,52 @@ if [[ -z "$DEPLOY_URL" ]]; then
     echo "Set RELEASE_DEPLOY_URL or RELEASE_DEPLOY_HOST, RELEASE_DEPLOY_USER, and RELEASE_DEPLOY_PASSWORD." >&2
     exit 1
   fi
-  DEPLOY_URL="ftp://${USER_NAME}:${PASSWORD}@${HOST}"
+  DEPLOY_URL="ftp://${HOST}"
+elif [[ -n "$USER_NAME" || -n "$PASSWORD" ]]; then
+  if [[ -z "$USER_NAME" || -z "$PASSWORD" ]]; then
+    echo "Set both RELEASE_DEPLOY_USER and RELEASE_DEPLOY_PASSWORD when providing deploy credentials separately." >&2
+    exit 1
+  fi
 fi
 
+lftp_quote() {
+  local value="${1//\'/\'\\\'\'}"
+  printf "'%s'" "$value"
+}
+
+run_lftp() {
+  local transfer_command="$1"
+
+  {
+    printf 'set ftp:ssl-allow true\n'
+    printf 'set ftp:ssl-force true\n'
+    printf 'set ftp:ssl-protect-data true\n'
+    printf 'set net:max-retries 3\n'
+    printf 'set net:timeout 20\n'
+
+    if [[ -n "$USER_NAME" && -n "$PASSWORD" ]]; then
+      printf 'open -u %s,%s %s\n' "$(lftp_quote "$USER_NAME")" "$(lftp_quote "$PASSWORD")" "$(lftp_quote "$DEPLOY_URL")"
+    else
+      printf 'open %s\n' "$(lftp_quote "$DEPLOY_URL")"
+    fi
+
+    printf 'cd %s\n' "$(lftp_quote "$REMOTE_ROOT")"
+    printf '%s\n' "$transfer_command"
+    printf 'bye\n'
+  } | lftp -f /dev/stdin
+}
+
 upload_file() {
   local source_file="$1"
   local remote_file="$2"
   if [[ -f "$source_file" ]]; then
-    lftp "$DEPLOY_URL" -e "set ftp:ssl-allow true; set net:max-retries 3; set net:timeout 20; cd \"$REMOTE_ROOT\"; put -O \"$(dirname "$remote_file")\" \"$source_file\" -o \"$(basename "$remote_file")\"; bye"
+    run_lftp "put -O $(lftp_quote "$(dirname "$remote_file")") $(lftp_quote "$source_file") -o $(lftp_quote "$(basename "$remote_file")")"
   fi
 }
 
 for directory in assets resources favicons icons img sounds .well-known; do
   if [[ -d "$DIST_DIR/$directory" ]]; then
-    lftp "$DEPLOY_URL" -e "set ftp:ssl-allow true; set net:max-retries 3; set net:timeout 20; cd \"$REMOTE_ROOT\"; mirror -R --only-newer --parallel=4 \"$DIST_DIR/$directory\" \"$directory\"; bye"
+    run_lftp "mirror -R --only-newer --parallel=4 $(lftp_quote "$DIST_DIR/$directory") $(lftp_quote "$directory")"
   fi
 done