CVE-2001-1356 in SurgeFTP
Summary
by MITRE
NetWin SurgeFTP 2.0f and earlier encrypts passwords using weak hashing, a fixed salt value and modulo 40 calculations, which allows remote attackers to conduct brute force password guessing attacks against the administrator account on port 7021.
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Analysis
by VulDB Data Team • 09/26/2025
The vulnerability identified in CVE-2001-1356 affects NetWin SurgeFTP version 2.0f and earlier implementations, presenting a critical security weakness in the password encryption mechanism that fundamentally undermines the authentication security model. This flaw resides in the cryptographic implementation used to store and verify administrator credentials, creating an exploitable condition that allows remote attackers to compromise system access without requiring legitimate credentials. The vulnerability specifically targets the password hashing process employed by the FTP server, which represents a fundamental failure in secure credential storage practices that has persisted for over two decades.
The technical implementation of the password encryption in SurgeFTP demonstrates several critical design flaws that collectively weaken the security posture. The system employs weak hashing algorithms combined with a fixed salt value that remains constant across all password encryptions, eliminating the primary defense mechanism that would normally prevent rainbow table attacks and make brute force attempts significantly more difficult. Additionally, the use of modulo 40 calculations in the encryption process introduces predictable patterns that further reduce the entropy of the resulting hash values. This combination of weak cryptographic primitives creates a scenario where attackers can systematically guess administrator passwords by leveraging the predictable nature of the hashing implementation. The vulnerability operates at the application layer and specifically targets the administrative interface accessible through port 7021, which serves as the primary attack vector for exploitation.
The operational impact of this vulnerability extends beyond simple credential compromise, as it enables unauthorized remote access to administrative functions within the FTP server environment. Attackers can systematically perform brute force attacks against the administrator account, potentially gaining full control over the file transfer server and its associated resources. The fixed salt value eliminates the security benefit of salting, which is a fundamental cryptographic practice designed to prevent attackers from using precomputed hash tables. This weakness allows attackers to perform parallelized brute force attacks against multiple accounts simultaneously, significantly reducing the time required to discover valid credentials. The vulnerability also impacts the overall security architecture by creating a persistent backdoor that remains exploitable until the software is patched or updated, potentially allowing attackers to maintain long-term access to the compromised system.
The weakness in SurgeFTP's implementation directly correlates to multiple cybersecurity standards and frameworks, particularly CWE-327 which addresses the use of weak cryptographic algorithms and CWE-328 which covers the use of weak hash functions. The vulnerability also aligns with ATT&CK technique T1110.003 which describes credential stuffing and password guessing attacks, and T1078.002 which covers valid accounts used for lateral movement. Organizations affected by this vulnerability should immediately implement mitigations including patching the software to a version that addresses the cryptographic weaknesses, implementing network segmentation to restrict access to port 7021, and enforcing strong password policies with multi-factor authentication where possible. The remediation process should also include monitoring for unauthorized access attempts and conducting comprehensive security assessments to identify any potential compromise from prior exploitation attempts. Given the age of this vulnerability and the availability of modern cryptographic standards, organizations should prioritize upgrading to supported software versions that implement industry-standard encryption practices including the use of strong hashing algorithms like bcrypt, scrypt, or PBKDF2 with randomized salt values.