CVE-2003-0831 in ProFTPD
Summary
by MITRE
ProFTPD 1.2.7 through 1.2.9rc2 does not properly translate newline characters when transferring files in ASCII mode, which allows remote attackers to execute arbitrary code via a buffer overflow using certain files.
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Analysis
by VulDB Data Team • 07/20/2025
The vulnerability identified as CVE-2003-0831 affects ProFTPD versions 1.2.7 through 1.2.9rc2 and represents a critical buffer overflow flaw that manifests during file transfers in ASCII mode. This issue stems from inadequate handling of newline character translation processes within the file transfer protocol implementation. The vulnerability specifically exploits the way the software manages carriage return and line feed characters when converting between different text formats during ASCII mode transfers.
The technical flaw occurs when ProFTPD processes files in ASCII mode, where it attempts to normalize line endings by translating carriage return and line feed sequences. The software fails to properly validate or bound-check the translated data before copying it into fixed-size buffers, creating conditions where maliciously crafted input files can exceed buffer boundaries. This buffer overflow vulnerability allows attackers to overwrite adjacent memory locations with crafted data, potentially leading to arbitrary code execution. The vulnerability is particularly dangerous because it operates during legitimate file transfer operations, making it difficult to detect through normal network monitoring.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise. Attackers can leverage this flaw to gain unauthorized access to systems running vulnerable ProFTPD versions, potentially escalating privileges and establishing persistent backdoors. The vulnerability affects any system that accepts file uploads or downloads through ProFTPD in ASCII mode, making it particularly concerning for web hosting providers and organizations relying on FTP services for data exchange. The attack vector requires only a single file transfer operation, making exploitation relatively straightforward and increasing the risk of successful compromise.
Mitigation strategies for this vulnerability include immediate patching of ProFTPD installations to versions 1.2.10 or later, which contain proper bounds checking and improved newline character handling. Organizations should also implement network segmentation to limit access to FTP services and deploy intrusion detection systems to monitor for suspicious file transfer patterns. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and maps to ATT&CK technique T1195.001 for content injection attacks. Additional defensive measures include disabling ASCII mode transfers when possible, implementing strict file validation policies, and conducting regular security assessments of FTP server configurations to prevent similar vulnerabilities from emerging in other protocols or services.