CVE-2005-3992 in WinEggDropShell
Summary
by MITRE
Multiple buffer overflows in WinEggDropShell remote access trojan (RAT) 1.7 allow remote attackers to execute arbitrary code via (1) a long GET request to the HTTP server, or a long (2) USER or (3) PASS command to the FTP server.
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Analysis
by VulDB Data Team • 07/14/2018
The vulnerability described in CVE-2005-3992 represents a critical security flaw within the WinEggDropShell remote access trojan version 1.7 that exposes multiple attack vectors through buffer overflow conditions. This malicious software component demonstrates the classic pattern of insecure input handling that has plagued network services for decades, creating opportunities for remote code execution that can compromise entire systems. The vulnerability affects both HTTP and FTP server implementations within the trojan, making it particularly dangerous as attackers can leverage different protocols to exploit the same underlying flaw.
The technical implementation of this vulnerability stems from inadequate bounds checking in the parsing of user-supplied input data. When the HTTP server receives a GET request with excessive data length, or when FTP server processes USER or PASS commands with oversized parameters, the software fails to validate input size before copying data into fixed-length buffers. This fundamental flaw falls under the common weakness category identified by CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The buffer overflow occurs because the trojan's server components do not implement proper input validation or length constraints, enabling attackers to craft malicious payloads that exceed allocated buffer space.
The operational impact of this vulnerability extends far beyond simple code execution capabilities, as it provides attackers with complete control over compromised systems. Once successfully exploited, the remote attacker gains the ability to execute arbitrary code with the privileges of the compromised service, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The trojan's design as a remote access tool means that successful exploitation directly translates to unauthorized access to network resources, making this vulnerability particularly attractive to threat actors seeking long-term system control. From an operational security perspective, the vulnerability's presence in a RAT implementation indicates that the software was designed with malicious intent from the outset, rather than being an accidental security flaw in legitimate software.
Mitigation strategies for this vulnerability must address both the immediate exploitation vectors and the underlying architectural weaknesses that enable such flaws. Organizations should implement network segmentation and firewall rules to restrict access to the affected services, particularly disabling unnecessary FTP and HTTP services on systems that might be vulnerable. The most effective remediation involves updating to patched versions of the software or removing the trojan entirely from affected systems, as the vulnerability cannot be effectively mitigated through configuration changes alone. Security teams should also deploy intrusion detection systems to monitor for unusual HTTP GET requests or FTP USER/PASS commands that might indicate exploitation attempts. This vulnerability demonstrates the importance of following secure coding practices as outlined in the software security guidelines, specifically addressing the need for robust input validation and proper buffer management techniques that prevent the conditions necessary for such exploits to succeed.
The presence of this vulnerability in a remote access trojan implementation aligns with tactics described in the MITRE ATT&CK framework under the T1059.007 technique for command and scripting interpreter, as exploitation enables attackers to execute arbitrary commands on compromised systems. Additionally, the vulnerability's nature reflects the broader threat landscape where attackers frequently target poorly secured network services, particularly those that handle user input without proper validation. The timing of this vulnerability, appearing in 2005, coincides with an era when many network services were not properly hardened against buffer overflow attacks, making such flaws common targets for malware authors seeking to create persistent access to compromised systems.