CVE-2017-7483 in Rxvt
Summary
by MITRE
Rxvt 2.7.10 is vulnerable to a denial of service attack by passing the value -2^31 inside a terminal escape code, which results in a non-invertible integer that eventually leads to a segfault due to an out of bounds read.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/24/2024
The vulnerability identified as CVE-2017-7483 affects Rxvt version 2.7.10, a terminal emulator software that has been widely used in Unix and Linux environments. This particular flaw represents a classic integer overflow condition that manifests through improper input validation within the terminal escape code processing mechanism. The vulnerability specifically targets the handling of negative integer values within escape sequences, creating a scenario where a maliciously crafted input can trigger unexpected behavior in the application's memory management routines.
The technical implementation of this vulnerability occurs when the terminal emulator processes escape codes containing the specific value of negative two to the power of thirty-one, which equates to -2147483648 in decimal notation. This value represents the minimum representable 32-bit signed integer and falls outside the normal range of valid integer operations within the application's processing pipeline. When Rxvt encounters this particular value within a terminal escape sequence, the integer processing routines fail to properly handle the boundary condition, resulting in an arithmetic overflow that produces a non-invertible integer state within the application's memory space.
The operational impact of this vulnerability manifests as a denial of service condition that ultimately results in a segmentation fault or segfault. This occurs because the malformed integer value causes an out of bounds memory read operation during the terminal escape code processing. The application's memory management system attempts to access memory locations that are either invalid or protected, leading to an abrupt termination of the process. This type of vulnerability is particularly concerning in terminal emulators as these applications often run with elevated privileges and may be used in critical system operations where availability is essential.
From a cybersecurity perspective, this vulnerability aligns with CWE-191, which describes integer underflow or overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1499.004 related to network denial of service attacks. The flaw represents a fundamental issue in input validation and integer handling within the terminal emulator's core processing logic, where proper bounds checking and error handling mechanisms are absent or insufficient. The vulnerability affects systems where Rxvt is installed and actively processing terminal escape sequences, potentially impacting any environment where this terminal emulator is utilized for command line operations, remote access, or system administration tasks.
The mitigation approach for this vulnerability requires immediate patching of the Rxvt application to version 2.7.11 or later, which includes proper integer bounds checking and overflow protection mechanisms. System administrators should also implement input validation controls at network boundaries where terminal emulators may be exposed to untrusted input, particularly in environments where remote terminal access is permitted. Additionally, monitoring for anomalous escape sequence patterns and implementing application-level sandboxing techniques can provide additional defense in depth. The vulnerability highlights the importance of robust integer handling in security-critical applications and demonstrates why proper input validation and bounds checking are essential components of secure software development practices.