CVE-2012-4425 in spice-gtk
Summary
by MITRE
libgio, when used in setuid or other privileged programs in spice-gtk and possibly other products, allows local users to gain privileges and execute arbitrary code via the DBUS_SYSTEM_BUS_ADDRESS environment variable. NOTE: it could be argued that this is a vulnerability in the applications that do not cleanse environment variables, not in libgio itself.
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Analysis
by VulDB Data Team • 12/29/2024
The vulnerability described in CVE-2012-4425 represents a critical privilege escalation issue affecting libgio, a core component of the GLib library used extensively in graphical applications and system utilities. This flaw specifically manifests when libgio is employed within setuid programs or other privileged contexts such as those found in spice-gtk, a virtualization client library. The vulnerability stems from the library's improper handling of the DBUS_SYSTEM_BUS_ADDRESS environment variable, which can be manipulated by local users to execute arbitrary code with elevated privileges. The technical nature of this vulnerability aligns with CWE-276, which addresses improper privileges, and more specifically with CWE-78, concerning command injection vulnerabilities. The issue occurs because libgio does not adequately sanitize or validate the DBUS_SYSTEM_BUS_ADDRESS environment variable before using it in privileged contexts, creating a potential attack vector for local adversaries.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security model of applications that rely on libgio for D-Bus communication. When applications running with elevated privileges process untrusted environment variables, they become susceptible to malicious input that can redirect system bus communications to attacker-controlled endpoints. This allows attackers to intercept, manipulate, or forge D-Bus messages that would normally be restricted to privileged processes, potentially leading to complete system compromise. The vulnerability's exploitation requires local access but can result in significant damage since it enables code execution with the privileges of the targeted setuid program. This type of attack pattern is consistent with ATT&CK technique T1548.001, which covers legitimate credentials and privilege escalation through setuid and setgid programs.
The fundamental flaw in libgio's implementation demonstrates a classic security oversight in environment variable handling within privileged execution contexts. Applications that utilize libgio for D-Bus communication may inadvertently inherit the vulnerability when they fail to properly cleanse their environment before invoking privileged operations. This vulnerability is particularly concerning because D-Bus is commonly used for system-level communication and service management, making the potential attack surface quite broad. The argument that this vulnerability lies primarily with applications rather than libgio itself is partially valid, as proper environment sanitization should be the responsibility of the calling applications. However, the widespread use of libgio across numerous applications and the difficulty of ensuring complete environment sanitization in all cases makes this a systemic security concern that requires attention at multiple levels of the software stack. Organizations should implement comprehensive environment variable validation and sanitization practices, particularly for applications that operate with elevated privileges and utilize D-Bus communication mechanisms.