CVE-2013-6774 in SuperSU
Summary
by MITRE
Untrusted search path vulnerability in the ChainsDD Superuser package 3.1.3 for Android 4.2.x and earlier, CyanogenMod/ClockWorkMod/Koush Superuser package 1.0.2.1 for Android 4.2.x and earlier, and Chainfire SuperSU package before 1.69 for Android 4.2.x and earlier allows attackers to load an arbitrary .jar file and gain privileges via a crafted BOOTCLASSPATH environment variable for a /system/xbin/su process. NOTE: another researcher was unable to reproduce this with ChainsDD Superuser.
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Analysis
by VulDB Data Team • 05/09/2026
The vulnerability described in CVE-2013-6774 represents a critical privilege escalation flaw affecting multiple SuperSU packages on Android systems prior to version 4.3. This issue stems from an insecure handling of the BOOTCLASSPATH environment variable during the execution of the su process located at /system/xbin/su. The vulnerability specifically impacts ChainsDD Superuser package version 3.1.3, CyanogenMod/ClockWorkMod/Koush Superuser package version 1.0.2.1, and Chainfire SuperSU package versions prior to 1.69 on Android 4.2.x and earlier systems. The flaw allows attackers to manipulate the classpath loading mechanism and execute arbitrary Java archive files with elevated privileges, effectively bypassing the intended security controls of the superuser access system.
This vulnerability operates through a classic untrusted search path attack vector where the system fails to properly validate or sanitize the BOOTCLASSPATH environment variable. When the su process executes, it loads classes from the specified path without adequate verification of the source or integrity of the loaded components. The attack exploits the fact that these superuser packages do not properly isolate or validate the classpath entries, allowing malicious actors to inject their own code by manipulating the environment variable. This creates a scenario where any attacker with local access can potentially load malicious .jar files that are then executed with root privileges, effectively compromising the entire system.
The operational impact of this vulnerability is severe as it enables full system compromise through privilege escalation. Attackers can leverage this flaw to execute arbitrary code with root privileges, potentially gaining complete control over the device including access to sensitive data, modification of system files, installation of malware, and persistence mechanisms. The vulnerability affects a wide range of Android devices running vulnerable versions, particularly those using custom recovery systems or modified ROMs where these superuser packages are commonly deployed. The attack requires local access to the device but does not need network connectivity or user interaction, making it particularly dangerous in scenarios where physical access is possible.
From a security standards perspective, this vulnerability maps directly to CWE-427 Uncontrolled Search Path Element, which describes the condition where a program uses a search path that can be manipulated by an attacker to load unauthorized code. The ATT&CK framework categorizes this under privilege escalation techniques, specifically T1068, which involves exploiting vulnerabilities to gain elevated privileges. The flaw also relates to T1548.001 which covers abuse of system permissions and T1059 which covers execution through scripting languages. Mitigation strategies should focus on updating to patched versions of the affected superuser packages, implementing proper environment variable validation, and ensuring that system components properly validate the integrity of loaded classes. System administrators should also consider implementing additional security measures such as SELinux policies, file integrity monitoring, and regular security audits to detect and prevent exploitation attempts.
The fact that another researcher was unable to reproduce the vulnerability with ChainsDD Superuser suggests that the issue may be specific to certain implementations or configurations of the superuser packages. However, the vulnerability remains a legitimate concern for the affected versions and configurations. The patching process for this vulnerability requires updating to newer versions of the superuser packages that properly address the environment variable handling and classpath loading mechanisms. Organizations should prioritize updating their Android devices to versions that include these security fixes and consider implementing additional runtime protections to prevent exploitation of similar vulnerabilities.