Stock traders sent defense companies surging in US markets as an attack on Israel from the Gaza-based militant group Hamas renewed Wall Street’s focus on the security industry. Shares of arms makers — including Northrop Gruman Corp, L3Harris Technologies Inc., Huntington Ingalls Industries Inc., Lockheed Martin Corp. and General Dynamics Corp. — led gains in the S&P 500 Index on Monday. The stocks each gained at least 8% in the session, the most in more than three years. The assault on Israel is sparking fresh concern about geopolitical risk among investors who’ve already been grappling with the impact of elevated...