CVE-2007-2877 in Tcl
Summary
by MITRE
Buffer overflow in tcl/win/tclWinReg.c in Tcl (Tcl/Tk) before 8.5a6 allows local users to gain privileges via long registry key paths.
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Analysis
by VulDB Data Team • 04/06/2019
The vulnerability identified as CVE-2007-2877 represents a critical buffer overflow flaw within the Tcl (Tool Command Language) implementation specifically affecting the Windows registry handling component. This issue exists in the tclWinReg.c file within the Tcl/Tk software suite and impacts versions prior to 8.5a6, creating a significant security risk for systems utilizing this scripting language framework. The flaw manifests when the software processes registry key paths that exceed predetermined buffer limits, allowing malicious input to overwrite adjacent memory locations and potentially execute arbitrary code with elevated privileges.
The technical nature of this vulnerability stems from improper bounds checking within the Windows registry access functions of Tcl. When a user provides a registry key path that exceeds the allocated buffer size, the software fails to validate the input length before copying it into memory. This classic buffer overflow condition enables attackers to craft specially designed registry key paths that overwrite critical memory segments including return addresses and function pointers. The vulnerability specifically affects the Windows implementation of Tcl, making it particularly dangerous in environments where Tcl scripts interact with the Windows registry, which often requires elevated privileges for system-level operations.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially compromise entire system architectures. Local users who can execute Tcl scripts with registry access capabilities can leverage this flaw to elevate their privileges to system level, effectively bypassing standard security controls. This presents a significant risk in environments where Tcl applications run with elevated permissions or where users have the ability to execute scripts that interact with the Windows registry. The vulnerability is particularly concerning because it allows for privilege escalation without requiring network access or complex exploitation techniques, making it highly attractive to attackers seeking persistent system control.
Mitigation strategies for CVE-2007-2877 primarily focus on immediate software updates and input validation measures. Organizations should prioritize upgrading to Tcl/Tk version 8.5a6 or later, which includes proper bounds checking for registry key path handling. Additionally, system administrators should implement strict input validation for all registry operations within Tcl applications, ensuring that registry key paths are properly sanitized before processing. The vulnerability aligns with CWE-121, which categorizes buffer overflow conditions in stack-based buffers, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves the use of privilege escalation techniques through local exploits. Network segmentation and privilege separation measures should also be implemented to limit the potential damage from successful exploitation attempts, particularly in environments where Tcl applications may be exposed to untrusted input sources.