A static technique for detecting input validation vulnerabilities in Android apps

Abstract

Input validation vulnerabilities are common in Android apps, especially in inter-component communications. Malicious attacks can exploit this kind of vulnerability to bypass Android security mechanism and compromise the integrity, confidentiality and availability of Android devices. However, so far there is not a sound approach at the source code level for app developers aiming to detect input validation vulnerabilities in Android apps. In this paper, we propose a novel approach for detecting input validation flaws in Android apps and we implement a prototype named EasyIVD, which provides practical static analysis of Java source code. EasyIVD leverages backward program slicing to extract transaction and constraint slices from Java source code. Then EasyIVD validates these slices with predefined security rules to detect vulnerabilities in a known pattern. To detect vulnerabilities in an unknown pattern, EasyIVD extracts implicit security specifications as frequent patterns from the duplicated slices and verifies them. Then EasyIVD semi-automatically confirms the suspicious rule violations and reports the confirmed ones as vulnerabilities. We evaluate EasyIVD on four versions of original Android apps spanning from version 2.2 to 5.0. It detects 58 vulnerabilities including confused deputy attacks and denial of service attacks. Our results prove that EasyIVD can provide a practical defensive solution for app developers.

创新点

为了检测在Android应用软件中较为普遍的输入验证漏洞, 本文提出了一种基于静态分析的挖掘方法并实现了一个原型系统EasyIVD。本文首先利用后向程序切片技术从Java源码中提取事务切片和约束切片, 再利用预定义的安全规则检测已知模式的输入验证漏洞。对于未知模式的输入验证漏洞, 本文从相似切片中提取频繁模式, 将之作为隐式安全规范来挖掘漏洞。本文将该系统应用在四个版本的Android系统原生应用上, 共挖掘出58个输入验证漏洞。