CVE-2006-0855 in zoo
Summary
by MITRE
Stack-based buffer overflow in the fullpath function in misc.c for zoo 2.10 and earlier, as used in products such as Barracuda Spam Firewall, allows user-assisted attackers to execute arbitrary code via a crafted ZOO file that causes the combine function to return a longer string than expected.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/15/2019
The vulnerability identified as CVE-2006-0855 represents a critical stack-based buffer overflow flaw within the zoo archive utility version 2.10 and earlier. This issue resides in the fullpath function located in the misc.c source file, which forms part of the broader zoo archive management system. The vulnerability manifests when processing specially crafted ZOO archive files that manipulate the combine function to return unexpectedly long string values. Such manipulation triggers a buffer overflow condition that can be exploited by malicious actors to execute arbitrary code on affected systems. The flaw specifically affects products that incorporate zoo 2.10 or earlier versions, including notable implementations such as the Barracuda Spam Firewall, making it particularly concerning for email security infrastructure. The vulnerability operates under the CWE-121 stack-based buffer overflow category, which is classified as a fundamental memory safety issue where data written to a stack buffer exceeds the buffer's allocated size. This type of vulnerability falls within the ATT&CK technique T1059.007 for command and script interpreter, as successful exploitation would enable attackers to execute arbitrary commands through the compromised system. The security implications extend beyond simple code execution to encompass potential privilege escalation and system compromise.
The technical mechanism behind this vulnerability involves the improper handling of string lengths during archive file processing. When the combine function processes file paths within the ZOO archive, it fails to properly validate or limit the length of the resulting string before passing it to the fullpath function. The fullpath function then attempts to store this potentially oversized string in a fixed-size stack buffer without adequate bounds checking. This lack of input validation creates a scenario where attacker-controlled data can overwrite adjacent stack memory, potentially corrupting program execution flow. The vulnerability is classified as user-assisted because it requires the attacker to create a malicious ZOO archive file that triggers the specific code path leading to the buffer overflow. The attack vector specifically targets the archive extraction process, where legitimate archive files are processed and decompressed, making it particularly dangerous in environments where automated archive processing occurs. The flaw demonstrates a classic buffer overflow pattern where the attacker must carefully construct input data to overflow the stack buffer and overwrite return addresses or other critical program state information.
The operational impact of CVE-2006-0855 extends significantly beyond simple code execution capabilities, potentially affecting entire network security infrastructures that rely on vulnerable zoo implementations. Systems utilizing affected versions of the Barracuda Spam Firewall or similar products incorporating zoo 2.10 or earlier face substantial risk of complete system compromise, as successful exploitation can lead to unauthorized access, data exfiltration, and persistent backdoor installation. The vulnerability affects not only individual host systems but also broader network security operations, particularly in email filtering and content inspection environments where archive files are routinely processed. Organizations running these vulnerable systems may experience service disruption, data breaches, and potential compliance violations, especially in regulated environments such as financial services or healthcare. The exploitation of this vulnerability can result in privilege escalation scenarios, allowing attackers to gain elevated system privileges and potentially move laterally within network environments. Network administrators must consider the broader implications for their security postures, as this vulnerability can be leveraged to establish persistent access points within protected environments, making it a significant concern for enterprise security operations.
Mitigation strategies for CVE-2006-0855 require immediate action to address the underlying vulnerability through software updates and system hardening measures. The primary recommendation involves upgrading to zoo version 2.11 or later, which includes proper bounds checking and input validation mechanisms that prevent the buffer overflow condition. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive timely updates, particularly those running Barracuda Spam Firewall or similar security appliances. Additionally, input validation controls should be implemented at multiple layers of the system architecture, including file format validation and size limitation for archive file processing. Network segmentation and access control measures can help limit the potential impact of successful exploitation attempts, while monitoring systems should be configured to detect anomalous archive processing activities. Security teams should also consider implementing sandboxing techniques for archive file handling and establishing strict file type restrictions for automated processing. The vulnerability's classification under CWE-121 emphasizes the need for robust memory safety practices in software development, including proper buffer size validation and defensive programming techniques. Organizations should conduct thorough vulnerability assessments to identify all systems potentially running affected versions of zoo and implement layered security controls to reduce the attack surface. Regular security testing and code reviews should be performed to identify similar memory safety issues in other software components, ensuring comprehensive protection against similar vulnerabilities in the future.