CVE-2003-0704 in KisMAC
Summary
by MITRE
KisMAC before 0.05d trusts user-supplied variables when chown ing files or directories, which allows local users to gain privileges via the $DRIVER_KEXT environment variable in (1) viha_driver.sh, (2) macjack_load.sh, (3) airojack_load.sh, (4) setuid_enable.sh, (5) setuid_disable.sh, and using a "similar technique" for (6) viha_prep.sh and (7) viha_unprep.sh.
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Analysis
by VulDB Data Team • 06/15/2018
This vulnerability exists in KisMAC versions prior to 0.05d and represents a critical privilege escalation flaw that leverages improper handling of user-supplied environment variables during system administration operations. The vulnerability specifically affects scripts that perform chown operations on files or directories, where the system fails to properly validate or sanitize the $DRIVER_KEXT environment variable before using it in privilege-sensitive contexts. The affected scripts include viha_driver.sh, macjack_load.sh, airojack_load.sh, setuid_enable.sh, setuid_disable.sh, viha_prep.sh, and viha_unprep.sh, all of which demonstrate a common pattern of insecure environment variable handling that enables local attackers to manipulate system permissions.
The technical flaw stems from the insecure use of environment variables in shell scripts without proper input validation or sanitization mechanisms. When these scripts execute chown commands, they directly incorporate the $DRIVER_KEXT variable into the command execution path without verifying its contents or ensuring it points to legitimate system resources. This creates a privilege escalation vector where an attacker can manipulate the environment variable to point to arbitrary files or directories, effectively allowing them to change ownership of critical system resources. The vulnerability aligns with CWE-78 and CWE-22, representing insecure use of system commands and improper limitation of a pathname to a restricted directory, respectively.
The operational impact of this vulnerability is significant as it allows local users to escalate their privileges from standard user level to root access, bypassing normal system security controls. Attackers can exploit this by setting the $DRIVER_KEXT environment variable to point to files they control, then executing the vulnerable scripts to gain unauthorized ownership of system resources. This technique leverages the principle of least privilege violation and can be used to modify system files, create backdoors, or establish persistent access to compromised systems. The vulnerability affects systems where KisMAC is installed and where users have the ability to execute the affected scripts, making it particularly dangerous in multi-user environments or systems with less restrictive access controls.
Mitigation strategies for this vulnerability include immediate patching to version 0.05d or later where the insecure environment variable handling has been corrected. System administrators should also implement proper environment variable validation and sanitization in all shell scripts that perform privilege-sensitive operations, particularly those involving chown, chmod, or similar system administration commands. The principle of least privilege should be enforced by limiting script execution permissions and ensuring that only authorized users can execute these critical system management scripts. Additionally, monitoring and logging of environment variable usage in system administration scripts can help detect potential exploitation attempts. This vulnerability demonstrates the importance of input validation and secure coding practices in shell scripting environments, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploits and T1548.1 which addresses privilege escalation through abuse of system permissions.