CVE-2000-0871 in EFTP
Summary
by MITRE
Buffer overflow in EFTP allows remote attackers to cause a denial of service by sending a string that does not contain a newline, then disconnecting from the server.
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Analysis
by VulDB Data Team • 05/05/2019
The vulnerability described in CVE-2000-0871 represents a classic buffer overflow condition within the EFTP (Extended File Transfer Protocol) implementation that was prevalent in early network services. This flaw specifically manifests when the EFTP server processes incoming data streams that lack proper line termination sequences, creating a scenario where memory allocation exceeds intended boundaries. The vulnerability resides in the protocol's handling of string inputs during connection establishment phases, where the software fails to properly validate or sanitize input data before processing it within fixed-length buffers.
The technical mechanism behind this vulnerability operates through improper input validation and buffer management within the EFTP server code. When a remote attacker sends a string containing data without a newline character termination, the server's internal buffer handling routines fail to account for this specific input pattern. This condition causes the program to write data beyond the allocated memory boundaries of the buffer, potentially overwriting adjacent memory locations. The flaw is particularly dangerous because it can be triggered without requiring authentication or special privileges, making it accessible to any remote attacker with network connectivity to the affected service.
From an operational perspective, this vulnerability enables a remote attacker to execute a denial of service attack against the targeted EFTP server. The attacker can simply establish a connection to the server, send a specially crafted string lacking newline characters, and then disconnect abruptly. This sequence of actions causes the server process to crash or become unresponsive, effectively denying legitimate users access to the file transfer service. The impact extends beyond simple service interruption as it can potentially lead to system instability, requiring manual intervention to restart affected services and restore normal operations.
The vulnerability aligns with CWE-121, which categorizes buffer overflow conditions occurring in stack-based buffers, and can be mapped to ATT&CK technique T1499.1, which covers network denial of service attacks. Organizations implementing EFTP services would have been particularly vulnerable as this flaw could be exploited by attackers to disrupt file transfer operations, potentially affecting business continuity and data availability. The attack vector requires minimal sophistication and can be automated, making it attractive to threat actors seeking to disrupt services without significant technical expertise. Proper input validation and buffer boundary checking mechanisms would have prevented this vulnerability by ensuring that all incoming strings are properly terminated before processing.
Mitigation strategies for this vulnerability would have included immediate software patching and updates to the EFTP implementation, along with implementing input sanitization measures that enforce proper string termination sequences. Network segmentation and access control measures could have limited the attack surface, while monitoring systems could have detected anomalous connection patterns indicating potential exploitation attempts. The vulnerability also highlighted the importance of proper buffer management practices in network service implementations, leading to improved coding standards and security testing procedures in subsequent software development cycles.