CVE-2017-17511 in KildClient
Summary
by MITRE
KildClient 3.1.0 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, related to prefs.c and worldgui.c.
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Analysis
by VulDB Data Team • 01/18/2023
The vulnerability identified as CVE-2017-17511 affects KildClient version 3.1.0, a web browser client implementation that fails to properly validate input strings before executing commands through the BROWSER environment variable. This represents a critical security flaw that enables remote attackers to manipulate the application's behavior through crafted URL inputs. The vulnerability stems from insufficient input validation mechanisms within the prefs.c and worldgui.c source code files, which handle preference settings and graphical user interface components respectively. When users navigate to maliciously crafted URLs, the application processes these inputs without adequate sanitization, creating an avenue for attackers to inject arbitrary command arguments.
The technical exploitation of this vulnerability occurs through argument injection attacks that leverage the BROWSER environment variable mechanism. Attackers can craft malicious URLs that, when processed by KildClient, cause the application to execute unintended commands with elevated privileges. The flaw specifically resides in the handling of user-supplied strings that are directly incorporated into system commands without proper validation or sanitization. This type of vulnerability falls under CWE-77, which categorizes improper neutralization of special elements used in commands, and more specifically aligns with CWE-94, representing inadequate control of generation of code, where the application dynamically generates commands that can be manipulated by attackers.
The operational impact of CVE-2017-17511 extends beyond simple command injection, potentially allowing attackers to execute arbitrary code on the affected system with the privileges of the KildClient application. Remote attackers can leverage this vulnerability to perform various malicious activities including but not limited to arbitrary command execution, privilege escalation, data exfiltration, and system compromise. The attack surface is particularly concerning as it requires no local access or authentication, making it suitable for remote exploitation across network boundaries. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059, which covers command and scripting interpreter, and T1203, representing legitimate credentials, as attackers can potentially escalate their privileges through successful exploitation.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization mechanisms throughout the application's codebase, particularly in the prefs.c and worldgui.c modules where the flaw originates. Organizations should immediately patch to newer versions of KildClient that address this validation issue, while also implementing defensive programming practices such as parameterized command execution and strict input filtering. Additional security measures include restricting environment variable modifications, implementing proper access controls, and monitoring for suspicious command execution patterns. The vulnerability demonstrates the critical importance of input validation in preventing command injection attacks and aligns with security best practices outlined in the OWASP Top Ten and NIST cybersecurity guidelines for preventing injection vulnerabilities. System administrators should also consider network-level protections such as firewall rules and intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability.