CVE-2007-0825 in FlashFXP
Summary
by MITRE
FlashFXP 3.4.0 build 1145 allows remote servers to cause a denial of service (CPU consumption) via a response to a PWD command that contains a long string with deeply nested directory structure, possibly due to a buffer overflow.
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Analysis
by VulDB Data Team • 08/22/2024
The vulnerability identified as CVE-2007-0825 affects FlashFXP version 3.4.0 build 1145, a popular file transfer client that implements the File Transfer Protocol. This issue represents a denial of service condition where remote servers can consume excessive cpu resources through a specifically crafted response to the PWD command. The flaw occurs when the ftp client receives a response containing an unusually long string with deeply nested directory structures, creating a scenario that can overwhelm the client's processing capabilities. This vulnerability falls under the category of buffer overflow conditions as described by CWE-121, where insufficient bounds checking allows for memory corruption through excessive data handling.
The technical implementation of this vulnerability exploits the client's handling of directory path responses during ftp operations. When FlashFXP processes a PWD command response, it fails to properly validate or limit the length of directory path strings, particularly those with deeply nested structures. The client's parsing routine likely iterates through the directory path characters without adequate bounds checking, leading to excessive cpu cycles as it attempts to process increasingly complex path structures. This behavior creates a resource exhaustion condition where the client's cpu usage spikes dramatically, effectively rendering the application unresponsive to legitimate user requests and causing a denial of service.
From an operational perspective, this vulnerability presents significant risks to users who may unknowingly connect to malicious ftp servers or encounter compromised servers in their network environment. The attack vector requires minimal privileges as it operates at the protocol level, making it particularly dangerous for automated systems or applications that rely on FlashFXP for file transfer operations. The impact extends beyond simple service interruption, as prolonged cpu consumption can lead to system instability, application crashes, and potential denial of service for other network services running on the same host system. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks that consume system resources.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and bounds checking within the ftp client's response parsing routines. System administrators should ensure that FlashFXP is updated to versions that address this specific buffer overflow condition, as the vendor likely released patches to limit string processing and implement proper memory management. Network-level protections such as ftp proxy servers or filtering rules can help prevent malicious responses from reaching the client, while monitoring systems should be configured to detect unusual cpu consumption patterns that may indicate exploitation attempts. Additionally, users should avoid connecting to untrusted ftp servers and implement connection restrictions to limit exposure to potentially malicious responses. The vulnerability demonstrates the critical importance of proper input validation and buffer management in client applications, particularly those handling network protocol responses where untrusted data sources exist.