CVE-2006-7098 in HTTP Server
Summary
by MITRE
The Debian GNU/Linux 033_-F_NO_SETSID patch for the Apache HTTP Server 1.3.34-4 does not properly disassociate httpd from a controlling tty when httpd is started interactively, which allows local users to gain privileges to that tty via a CGI program that calls the TIOCSTI ioctl.
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Analysis
by VulDB Data Team • 01/28/2025
The vulnerability described in CVE-2006-7098 represents a critical privilege escalation issue within the Apache HTTP Server 1.3.34-4 package distributed with Debian GNU/Linux. This flaw emerged from a specific patch implementation that failed to properly handle the disassociation of the httpd process from its controlling terminal when the server was launched interactively. The root cause lies in the improper handling of process control terminal management, which creates a security boundary violation that malicious local users can exploit to gain unauthorized access to terminal sessions.
The technical mechanism behind this vulnerability involves the TIOCSTI ioctl system call that can be invoked through CGI programs. When httpd is started interactively, the patch fails to completely detach the process from the controlling tty, leaving the terminal session accessible to processes spawned by CGI scripts. This allows a local attacker to execute a CGI program that invokes TIOCSTI, effectively injecting keystrokes into the terminal session. The ioctl call can redirect input to the terminal, potentially enabling attackers to escalate privileges by gaining access to the terminal session that was previously restricted.
This vulnerability directly maps to CWE-250: "Execute Code with Unusual/Unorthodox Privileges" and represents a privilege escalation flaw that operates through terminal session manipulation. The operational impact extends beyond simple local privilege escalation as it can enable attackers to gain access to terminal sessions that might contain sensitive information or provide access to other system resources. The issue is particularly concerning in multi-user environments where terminal sessions might be shared or contain administrative credentials.
The attack vector requires local access and involves the exploitation of a specific interaction between process control mechanisms and CGI execution capabilities. Attackers must first gain access to the system as a local user, then craft or obtain a CGI program that can invoke the TIOCSTI ioctl call. The vulnerability demonstrates a fundamental flaw in process management and terminal session handling that violates the principle of least privilege. Organizations running affected Apache versions should immediately implement mitigations, including proper process isolation, terminal session management, and regular updates to address the underlying patch implementation issues.
From an ATT&CK framework perspective, this vulnerability aligns with T1068: "Exploitation for Privilege Escalation" and T1059.006: "Command and Scripting Interpreter: Python", where the exploitation occurs through the execution of CGI scripts. The vulnerability represents a failure in system call filtering and process control that enables attackers to manipulate terminal sessions through legitimate system interfaces. Security professionals should implement monitoring for suspicious TIOCSTI ioctl usage patterns and ensure proper process isolation mechanisms are in place to prevent unauthorized terminal session access. The patch for this vulnerability should be applied immediately to prevent exploitation, as the underlying issue affects the fundamental process management capabilities of the Apache HTTP Server when running in interactive mode.