CVE-2018-20181 in rdesktop
Summary
by MITRE
rdesktop versions up to and including v1.8.3 contain an Integer Underflow that leads to a Heap-Based Buffer Overflow in the function seamless_process() and results in memory corruption and probably even a remote code execution.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/01/2023
The vulnerability identified as CVE-2018-20181 represents a critical security flaw affecting rdesktop versions up to and including v1.8.3, which exposes users to potential remote code execution risks. This issue stems from an integer underflow condition that propagates into a heap-based buffer overflow within the seamless_process() function, creating a chain of memory corruption vulnerabilities that can be exploited by remote attackers.
The technical flaw manifests through an integer underflow condition that occurs when processing certain data structures within the seamless communication protocol implementation. When the seamless_process() function handles incoming data, it performs arithmetic operations that can result in integer underflow, where a subtraction operation produces a value smaller than the minimum representable integer. This underflow condition directly leads to improper memory allocation calculations, causing the heap-based buffer overflow to occur when the application attempts to write data beyond the allocated buffer boundaries.
The operational impact of this vulnerability extends beyond simple memory corruption, as it creates a pathway for remote code execution attacks that can compromise entire systems. Attackers exploiting this vulnerability can manipulate the memory layout of the rdesktop application to inject malicious code, potentially gaining full control over the target system. The heap-based nature of the buffer overflow provides attackers with additional flexibility in exploitation techniques, as heap corruption can be leveraged to achieve arbitrary code execution through various attack vectors including return-oriented programming and function pointer overwrites.
This vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and demonstrates how seemingly minor arithmetic errors can lead to catastrophic security implications. The ATT&CK framework categorizes this type of vulnerability under the T1059.007 technique for "Command and Scripting Interpreter: PowerShell" and similar execution methods, as successful exploitation would likely involve command injection or code execution payloads. The vulnerability's classification as a heap-based buffer overflow also connects to ATT&CK's T1068 technique for 'Exploitation for Privilege Escalation' and T1203 technique for 'Exploitation of Remote Services' when considering the remote attack surface.
Mitigation strategies for CVE-2018-20181 should prioritize immediate patching of affected rdesktop installations to version 1.8.4 or later, which contains the necessary fixes for the integer underflow condition. Organizations should also implement network segmentation and access controls to limit exposure to the affected services, while monitoring for suspicious network traffic patterns that might indicate exploitation attempts. Additional defensive measures include deploying intrusion detection systems with signatures specific to rdesktop exploitation patterns and conducting regular security assessments to identify other potential vulnerabilities in remote desktop implementations. The vulnerability highlights the importance of thorough input validation and integer arithmetic checking in network protocol implementations, particularly those handling untrusted data from remote sources.