CVE-2013-6825 in DCMTK
Summary
by MITRE
(1) movescu.cc and (2) storescp.cc in dcmnet/apps/, (3) dcmnet/libsrc/scp.cc, (4) dcmwlm/libsrc/wlmactmg.cc, (5) dcmprscp.cc and (6) dcmpsrcv.cc in dcmpstat/apps/, (7) dcmpstat/tests/msgserv.cc, and (8) dcmqrdb/apps/dcmqrscp.cc in DCMTK 3.6.1 and earlier does not check the return value of the setuid system call, which allows local users to gain privileges by creating a large number of processes.
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Analysis
by VulDB Data Team • 08/25/2025
The vulnerability identified as CVE-2013-6825 affects the DCMTK (DICOM Toolkit) version 3.6.1 and earlier, specifically within several network application components that handle DICOM protocol communications. This flaw resides in the privilege management mechanisms of multiple files including movescu.cc, storescp.cc, scp.cc, wlmactmg.cc, dcmpsrcv.cc, msgserv.cc, and dcmqrscp.cc, all of which are part of the DICOM network communication stack. The vulnerability stems from improper error handling in the setuid system call execution, which is a critical security mechanism used to change process privileges during execution. When these applications execute with elevated privileges to perform network operations, they should verify that the privilege change was successful before proceeding with operations that require administrative rights. The failure to check the return value of setuid calls creates a scenario where local attackers can exploit this weakness to escalate their privileges within the system.
This vulnerability represents a classic privilege escalation issue that aligns with CWE-252, which describes "Unchecked Return Value" in security contexts. The technical flaw occurs when applications attempt to change their effective user ID from root to a less privileged user account, but fail to validate whether this operation succeeded. The setuid system call, when properly implemented, should return zero on success or a negative value on failure. However, in the affected DCMTK applications, developers omitted the necessary validation checks, allowing the applications to continue execution even when the privilege change failed. This creates a persistent security weakness that local users can exploit by repeatedly creating processes, potentially causing the system to enter an inconsistent state where privilege checks are bypassed. The vulnerability is particularly dangerous because it affects core network services that typically run with elevated privileges to bind to privileged network ports and access system resources.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass broader system compromise scenarios. Attackers can leverage this weakness to gain root access to systems running affected DCMTK applications, which are commonly deployed in healthcare environments where DICOM protocol communications are critical for medical imaging systems. The ability to create numerous processes allows attackers to repeatedly attempt privilege escalation until successful, making this vulnerability particularly effective in automated exploitation scenarios. This flaw is especially concerning in healthcare settings where DICOM servers often run with root privileges to manage medical imaging databases and network communications. The vulnerability can be exploited by any local user who has access to the system, potentially allowing unauthorized individuals to gain administrative control over medical imaging servers, which could lead to data breaches, system compromise, and disruption of critical healthcare services. Additionally, since these applications are part of the DICOM standard implementation, the vulnerability affects a wide range of medical imaging systems that rely on DCMTK for network communications.
Mitigation strategies for CVE-2013-6825 should focus on immediate patching of the affected DCMTK versions to address the unchecked return value issue in setuid calls. Organizations should ensure that all instances of the affected applications properly validate the return values of setuid system calls before proceeding with privilege-dependent operations. The recommended approach involves implementing proper error handling mechanisms that verify successful privilege changes and terminate execution if the setuid call fails. Security administrators should also consider running these applications with minimal required privileges rather than root privileges, using privilege separation techniques that align with the principle of least privilege. Additionally, system monitoring should be enhanced to detect unusual process creation patterns that might indicate exploitation attempts. This vulnerability demonstrates the importance of proper error handling in security-critical code and aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." Organizations should also implement network segmentation and access controls to limit local user access to these critical applications, reducing the attack surface for privilege escalation exploits. The fix should be applied across all medical imaging systems, PACS servers, and any other infrastructure that utilizes the vulnerable DCMTK components to ensure comprehensive protection against this and similar privilege escalation vulnerabilities.