CVE-2008-4748 in KVirc
Summary
by MITRE
Format string vulnerability in the URI handler in KVirc 3.4.0, when set as the default application for processing IRC URIs, allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via format string specifiers in the irc:// URI.
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Analysis
by VulDB Data Team • 11/09/2024
The vulnerability described in CVE-2008-4748 represents a critical format string vulnerability within the URI handling mechanism of KVirc version 3.4.0. This issue specifically affects the application's ability to process irc:// URIs when KVirc is configured as the default handler for such links. The flaw arises from improper input validation and sanitization of URI parameters, creating a dangerous condition where user-supplied data can be interpreted as format specifiers rather than literal text. When a maliciously crafted URI is processed, the application fails to properly escape or validate the input before passing it to format string functions, leading to unpredictable behavior.
The technical exploitation of this vulnerability occurs through the manipulation of URI parameters that contain format string specifiers such as %s, %d, or %x. When the application attempts to process these malformed URIs, it passes the unvalidated input directly to functions like printf or sprintf without proper sanitization. This creates a classic format string vulnerability that can be leveraged to trigger application crashes, potentially leading to denial of service conditions, or more severely, arbitrary code execution. The vulnerability is particularly dangerous because it can be triggered through normal user interactions when clicking on malicious links, making it a remote attack vector that requires no local privileges.
The operational impact of this vulnerability extends beyond simple application instability to potentially compromise entire systems. When exploited successfully, attackers can cause KVirc to crash and restart repeatedly, creating a denial of service condition that prevents legitimate users from accessing IRC services. More critically, the format string vulnerability can be weaponized to execute arbitrary code with the privileges of the user running KVirc, potentially allowing attackers to gain unauthorized access to system resources. This vulnerability affects users who have KVirc configured as their default IRC client, making it particularly dangerous in environments where users frequently click on external links. The attack surface is broad since any application or website that generates irc:// URIs can potentially serve as an attack vector.
Mitigation strategies for CVE-2008-4748 should focus on immediate patching of the affected KVirc version, as this vulnerability was addressed in subsequent releases. System administrators should ensure that all instances of KVirc are updated to versions that properly sanitize URI inputs and implement proper input validation before processing format string arguments. Users should be educated about the risks of clicking on untrusted links and should avoid setting potentially vulnerable applications as default handlers for URI schemes. Network-level protections can include implementing URI filtering rules that prevent the processing of suspicious format string patterns, while application-level defenses should enforce strict input validation and use safe string formatting functions such as snprintf instead of sprintf. This vulnerability aligns with CWE-134 which specifically addresses format string vulnerabilities, and represents a typical entry point for attackers following ATT&CK technique T1203 for legitimate access and privilege escalation through application exploitation. The vulnerability demonstrates the critical importance of proper input validation and secure coding practices in preventing remote code execution through seemingly benign user interaction points.