CVE-2006-1038 in SecureFX
Summary
by MITRE
Buffer overflow in SecureCRT 5.0.4 and earlier and SecureFX 3.0.4 and earlier allows remote attackers to have an unknown impact when a Unicode string is converted to a "narrow" string.
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Analysis
by VulDB Data Team • 07/20/2018
The vulnerability identified as CVE-2006-1038 represents a critical buffer overflow flaw affecting SecureCRT 5.0.4 and earlier versions, as well as SecureFX 3.0.4 and earlier versions. This vulnerability specifically manifests during the conversion process of Unicode strings to "narrow" strings, creating a potential exploitation vector for remote attackers. The flaw resides in the improper handling of character encoding transformations that occur within the secure communication software, where the application fails to adequately validate the length of Unicode data before converting it to a narrow string format suitable for processing. This type of vulnerability falls under the CWE-121 category of buffer overflow conditions, where insufficient bounds checking allows attackers to write beyond allocated memory boundaries.
The technical exploitation of this vulnerability occurs when a remote attacker crafts malicious Unicode input that, upon conversion to narrow string format, exceeds the allocated buffer space. The conversion process from wide to narrow character strings typically involves character set transformations that may not properly account for the variable length nature of Unicode encoding. When the application attempts to store the converted string in a fixed-size buffer, it can overwrite adjacent memory locations, potentially leading to arbitrary code execution or application crashes. This vulnerability demonstrates the classic buffer overflow pattern where the flaw exists in the string manipulation routines rather than in the core application logic, making it particularly dangerous as it can be triggered through normal network communication channels.
The operational impact of this vulnerability extends beyond simple application instability, as it provides attackers with potential pathways to execute arbitrary code on vulnerable systems. When exploited successfully, the buffer overflow could allow remote attackers to gain unauthorized access to systems running affected versions of SecureCRT or SecureFX, potentially leading to complete system compromise. The vulnerability affects both terminal emulation and file transfer functionalities, making it particularly concerning for organizations that rely on these tools for secure remote access and data transfer operations. Organizations using these applications in production environments face significant risk as the vulnerability can be exploited without requiring authentication, making it a particularly attractive target for automated attacks.
Mitigation strategies for CVE-2006-1038 should prioritize immediate software updates to versions that address the buffer overflow in string conversion routines. Organizations should implement network segmentation and access controls to limit exposure of vulnerable systems, while also monitoring for suspicious network activity that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute commands on compromised systems. Security teams should also consider implementing input validation measures at network boundaries to filter out potentially malicious Unicode sequences before they reach vulnerable applications. Additionally, regular security assessments and penetration testing should be conducted to identify similar encoding-related vulnerabilities in other applications and systems within the organization's infrastructure.