CVE-2006-4654 in Easy Address Book Web Server
Summary
by MITRE
Format string vulnerability in Easy Address Book Web Server 1.2 allows remote attackers to cause a denial of service (crash) or "compromise the server" via encoded format string specifiers in the query string.
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Analysis
by VulDB Data Team • 06/25/2019
The vulnerability identified as CVE-2006-4654 represents a critical format string flaw within the Easy Address Book Web Server version 1.2 that exposes the system to remote exploitation. This type of vulnerability falls under the category of improper input validation where the application fails to properly sanitize user-supplied data before processing it through format string functions. The flaw specifically manifests when the web server processes query string parameters containing encoded format specifiers, which are typically used in programming functions like printf and sprintf to control output formatting. When these specifiers are not properly escaped or validated, they can be manipulated to execute arbitrary code or trigger unexpected behavior within the application's memory management.
The technical implementation of this vulnerability stems from the web server's failure to implement proper input sanitization routines for HTTP query parameters. Attackers can craft malicious URLs containing format string specifiers such as %s, %d, or %x within the query string, which are then processed by the server's internal functions without adequate validation. This lack of input filtering creates a pathway for exploitation where the server's memory structures can be manipulated through carefully crafted payloads. The vulnerability is particularly dangerous because it operates at the application level and can be exploited remotely without requiring any authentication or prior access to the system. The flaw is classified as a CWE-134 vulnerability, which specifically addresses the use of untrusted data in format string contexts, making it a well-documented and serious security concern within the software development community.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable complete server compromise. While the primary effect may manifest as a crash or restart of the web server process, the underlying nature of format string vulnerabilities allows for more sophisticated exploitation techniques. Attackers can leverage this weakness to overwrite memory locations, execute arbitrary code, or even escalate privileges within the system. The server's response to malformed format specifiers could be exploited to gain unauthorized access to sensitive data or system resources, making this vulnerability particularly attractive to threat actors. According to ATT&CK framework categorization, this vulnerability aligns with T1059.007 for command and scripting interpreter and T1499.004 for network denial of service, demonstrating both the immediate availability impact and potential for broader system compromise.
Mitigation strategies for CVE-2006-4654 require immediate implementation of input validation and sanitization measures within the web server's request processing pipeline. The most effective approach involves implementing strict parameter validation that rejects or properly escapes any format string specifiers present in query parameters before they are processed by any formatting functions. Organizations should also consider applying the latest security patches from the vendor if available, though this particular vulnerability affects an older version of the software that may no longer receive support. Network-level protections such as web application firewalls can provide additional defense-in-depth by filtering out suspicious query parameters containing format string patterns. Regular security assessments and code reviews should be conducted to identify similar vulnerabilities in other applications and ensure that proper input validation routines are consistently implemented throughout the software stack. System administrators should also monitor for unusual server behavior or crash patterns that might indicate exploitation attempts.