Security researchers have compromised Microsoft Surface RT, Nexus 4 and Samsung Galaxy S4 devices by exploiting previously unknown vulnerabilities in Internet Explorer 11 running on Windows 8.1 and Google Chrome running on Android.The exploits were demonstrated during the Mobile Pwn2Own hacking contest that ran Wednesday and Thursday at the PacSec Applied Security Conference in Tokyo.Researchers Abdul Aziz Hariri and Matt Molinyawe from Hewlett-Packard's Zero Day Initiative (ZDI) team, which organized the contest, demonstrated an Internet Explorer 11 exploit on a Microsoft Surface RT device running Windows 8.1."Exploiting a bug in IE is difficult in general because of the protections and security controls they've implemented," Hariri said. The vulnerability was exploited twice in order to leak a memory address and then gain remote code execution, "which gave us full control over the whole machine," he said.The vulnerability was reported to Microsoft so the company can protect users, Molinyawe said.Another researcher who uses the pseudonym Pinkie Pie compromised Nexus 4 and Samsung Galaxy S4 devices by exploiting a vulnerability in Chrome.Achieving remote code execution through a Chrome vulnerability is considered very difficult because of the application sandbox that separates the browser's processes from the operating system.There have been only a handful of Chrome sandbox escape exploits demonstrated over the years and most of them were presented by researchers at hacking contests. Pinkie Pie hacked Chrome's sandbox two times before in 2012 as part of Google's Pwnium contests.The researcher's new Chrome exploit chained together an integer overflow vulnerability and a sandbox escape one, earning him a prize of US$50,000.The standard prize for compromising a mobile device through a Web browser at Mobile Pwn2Own was $40,000, but the Google Chrome Security Team offered a $10,000 bonus if the hacked browser was Chrome running on Nexus 4 or Samsung Galaxy S4.Pinkie Pie secured the win by demonstrating his exploit on Nexus 4, but then for show, he repeated the feat on Samsung Galaxy S4.In order for the attack to work the potential victim has to click on a link to a specifically crafted Web page sent via email, SMS or found on another website. Once the malicious page is opened in Chrome, the attack executes without any other user interaction and allows arbitrary code execution on the operating system.As the contest rules dictate, the vulnerabilities exploited by Pinkie Pie were reported to Google so they can be fixed.The Mobile Pwn2Own contest ended with participating researchers winning $117,500 out of a prize pool of over $300,000.A team of security researchers from Japanese company Mitsui Bussan Secure Directions hacked into a Samsung Galaxy S4 device by exploiting vulnerabilities in unnamed applications pre-installed on the device by the manufacturer. A team of Chinese researchers hacked into two iPhone 5 devices running iOS 7.0.3 and iOS 6.1.4 respectively by exploiting vulnerabilities in Safari.The Japanese team won $40,000 because their attack resulted in a full compromise of the device, and the Chinese team won $27,500 because their attack resulted in theft of data, like session cookies, photos and contacts.