CVE-2017-17525 in xTuple PostBooks
Summary
by MITRE
guiclient/guiclient.cpp in xTuple PostBooks 4.7.0 does not validate strings before launching the program specified by the BROWSER environment variable, which might allow remote attackers to conduct argument-injection attacks via a crafted URL.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 12/15/2019
The vulnerability identified as CVE-2017-17525 resides within the guiclient component of xTuple PostBooks version 4.7.0, specifically in the guiclient.cpp file. This flaw represents a classic command injection vulnerability that arises from insufficient input validation mechanisms. The application fails to properly sanitize user-supplied strings before utilizing them in the execution of external programs, creating a dangerous attack surface where malicious actors can manipulate the BROWSER environment variable to execute arbitrary commands on the target system. The vulnerability is particularly concerning because it operates at the application layer where user input is processed, making it accessible to remote attackers who can craft malicious URLs to exploit this weakness.
The technical implementation of this vulnerability stems from improper string validation and sanitization practices within the application's codebase. When xTuple PostBooks processes URLs containing browser references, it directly incorporates user-provided strings into the BROWSER environment variable without adequate filtering or escaping mechanisms. This design flaw aligns with CWE-74, which describes weaknesses related to improper neutralization of special elements used in data queries, and CWE-78, which addresses improper neutralization of special elements used in command execution. The attack vector involves remote exploitation where an attacker crafts a malicious URL that, when processed by the vulnerable application, results in the execution of unintended shell commands through the BROWSER environment variable mechanism. This represents a fundamental failure in input validation and secure coding practices that violates core principles of defensive programming.
The operational impact of CVE-2017-17525 extends beyond simple privilege escalation to encompass full system compromise capabilities for remote attackers. An attacker who successfully exploits this vulnerability can execute arbitrary code with the privileges of the user running the xTuple PostBooks application, potentially leading to complete system takeover. The vulnerability can be leveraged to perform various malicious activities including but not limited to data exfiltration, system reconnaissance, privilege escalation, and installation of backdoors or additional malware. From an adversary perspective, this vulnerability maps directly to ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, providing attackers with a reliable method for executing malicious payloads and maintaining persistence. The remote nature of the attack means that exploitation can occur without physical access to the target system, making it particularly dangerous in enterprise environments where such applications may be exposed to untrusted networks.
Mitigation strategies for CVE-2017-17525 should focus on implementing proper input validation and sanitization mechanisms throughout the application's codebase. Organizations should immediately upgrade to patched versions of xTuple PostBooks where available, as the vulnerability has been addressed in subsequent releases. The implementation of secure coding practices including parameter validation, environment variable sanitization, and proper command execution mechanisms should be enforced. Additionally, network-level protections such as firewalls and intrusion detection systems can help detect and prevent exploitation attempts. From a defensive standpoint, implementing application whitelisting policies and restricting the BROWSER environment variable's usage can significantly reduce the attack surface. Organizations should also consider deploying web application firewalls and monitoring for suspicious URL patterns that may indicate exploitation attempts. The vulnerability highlights the importance of adhering to secure coding standards and conducting regular security assessments to identify and remediate similar weaknesses in enterprise applications.