Orange Tsai - Infiltrating Corporate Intranet Like NSA Preauth RCE - DEF CON 27 Conference
Channel: DEFCONConference
Date: 2019-11-16

Computer security is now a public policy issue. Election security, blockchain, "going dark," the vulnerabilities equities debate, IoT safety , data privacy, algorithmic security and fairness, critical infrastructure: these are all important public policy issues with a strong Internet security component. But while an understanding of the technology involved is fundamental to crafting good policy, there is little involvement of technologists in policy discussions. This is not sustainable. We need public-interest technologists: people from our fields helping craft policy, and working to provide security to agencies and groups working in the broader public interest. We need these people in government, at NGOs, teaching at universities, as part of the press, and inside private companies. This is increasingly critical to both public safety and overall social welfare. This talk both describes the current state of public-interest technology, and offers a way forward for us individually and collectively for our field. The defining policy question of the Internet age is this: How much of our lives should be governed by technology, and under what terms? We need to be involved in that debate.SSL VPNs protect corporate assets from Internet exposure, but what if SSL VPNs themselves are vulnerable? They’re exposed to the Internet, trusted to reliably guard the only way to intranet. However, we found pre-auth RCEs on multiple leading SSL VPNs, used by nearly half of the Fortune 500 companies and many government organizations. To make things worse, a “magic” backdoor was found to allow changing any user’s password with no credentials required! To show how bad things can go, we will demonstrate gaining root shell from the only exposed HTTPS port, covertly weaponizing the server against their owner, and abusing a hidden feature to take over all VPN clients!

In such complicated closed-source systems, gaining root shell from outside the box certainly ain’t easy. It takes advanced web and binary exploitation techniques to struggle for a way to root shell, which involves abusing defects in web architectures, hard-core Apache jemalloc exploitation and more. We will cover every detail of all the dirty tricks, crazy bug chains, and the built-in backdoor. After gaining root shell into the box, we then elaborate on post exploitation and how we hack back the clients. In addition, we will share the attack vectors against SSL VPNs to kick start researches on similar targets. On the other hand, from our previous experience, we derive general hardening actions that mitigate not only all the above attacks, but any other potential 0days.

In summary, we disclose practical attacks capable of compromising millions of targets, including tech giants and many industry leaders. These techniques and methodologies are published in the hope that it can inspire more security researchers to think out-of-the-box; enterprises can apply immediate mitigation, and realize that SSL VPN is not merely Virtual Private Network, but also a “Vulnerable Point of your Network”.

Orange Tsai
Cheng-Da Tsai, also as known as Orange Tsai, is the principal security research of DEVCORE and the member of CHROOT security group from Taiwan. He has spoken at conferences such as Black Hat USA/ASIA, DEF CON, HITCON, HITB, Hack.lu and CODEBLUE. He participates in numerous Capture-the-Flags (CTF), and also the team captain of HITCON, which won 2nd place in DEF CON 22/25. Currently, he is focusing on application security and 0day research. Orange enjoys finding vulnerabilities and participating in Bug Bounty Programs. He is enthusiastic about Remote Code Execution (RCE), and uncovered RCEs in several vendors, such as Facebook, Uber, Apple, GitHub, Amazon, Yahoo, Netflix and Imgur.

Twitter: @orange_8361
Website: http://blog.orange.tw/

Meh Chang
Tingyi Chang, also known as Meh Chang, is a security researcher at DEVCORE. She focuses on binary program analysis and exploitation. She is a member of HITCON and 217 CTF team and has won the second place of DEF CON 25.

Twitter: @mehqq_