数值稳定性相关漏洞隐患的自动化检测方法

安全漏洞检测是保障软件安全性的重要手段.随着互联网的发展，黑客的攻击手段日趋多样化，且攻击技术不断翻新，使软件安全受到了新的威胁.本文描述了当前软件中实际存在的一种新类型的安全漏洞隐患，我们称之为数值稳定性相关的安全漏洞隐患.由于黑客可以利用该类漏洞绕过现有的防护措施，且已有的数值稳定性分析方法很难检测到该类漏洞的存在，因而这一新类型的漏洞隐患十分危险.面对这一挑战，本文首先从数值稳定性引起软件行为改变的角度定义了数值稳定性相关的安全漏洞隐患，并给出了对应的自动化检测方法.该方法基于动静态相结合的程序分析与符号执行技术，通过数值变量符号式提取、静态攻击流程分析、以及高精度动态攻击验证三个步骤，来检测和分析软件中可能存在的数值稳定性相关安全漏洞.我们在业界多个著名开源软件上进行了实例研究，实验结果表明，本文方法能够有效检测到实际软件中真实存在的数值稳定性相关漏洞隐患.

Method for Automated Detection of Suspicious Vulnerability Related to Numerical Stability

Vulnerability detection is an important way of improving the security of software. However, the development of the Internet makes it possible for hackers to attack software systems with new techniques. So the software is still vulnerable. This paper describes a new kind of vulnerability. We call it the vulnerability related to numerical stability. As hackers are able to bypass the security protection by the new kind of vulnerability, and numerical analysis is difficult to detect such a vulnerability, it is dangerous. In this paper, we define the vulnerability related to numerical stability from the perspective of software behavior variation caused by numerical errors, and further propose an automatic detection approach. The approach combines the static analysis and symbolic execution, and detects the vulnerability by three steps: symbolic extraction, static attack analysis, and dynamic attack verification with high precision values. We evaluate our approach on a few famous open source projects. The results show that our approach effectively detects the vulnerabilities related to numerical stability hidden in the real-world projects.