CVE-2005-2661 in up-imapproxy
Summary
by MITRE
Format string vulnerability in the ParseBannerAndCapability function in main.c for up-imapproxy 1.2.3 and 1.2.4 allows remote IMAP servers to execute arbitrary code via format string specifiers in a banner or capability line.
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Analysis
by VulDB Data Team • 12/24/2024
The CVE-2005-2661 vulnerability represents a critical format string flaw in the up-imapproxy software version 1.2.3 and 1.2.4, specifically within the ParseBannerAndCapability function located in the main.c source file. This vulnerability arises from improper input validation and handling of IMAP server responses, creating a pathway for remote code execution attacks. The flaw occurs when the proxy processes banner or capability lines returned by IMAP servers, which are typically used to establish initial communication and negotiate supported features between client and server components.
The technical nature of this vulnerability stems from the function's reliance on untrusted data without proper sanitization before being passed to format string functions such as printf or sprintf. When an attacker-controlled IMAP server responds with maliciously crafted banner or capability lines containing format specifiers, the proxy software interprets these strings as format directives rather than literal text. This misinterpretation allows attackers to manipulate memory layout, potentially leading to arbitrary code execution with the privileges of the proxy process. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous in networked environments where IMAP traffic flows through the proxy.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can enable full system compromise when the proxy runs with elevated privileges. Attackers can leverage this flaw to inject malicious code into the proxy process, potentially gaining access to all IMAP traffic passing through the system, including sensitive email communications and authentication credentials. The vulnerability affects the integrity and confidentiality of email communications, as well as potentially providing a foothold for further network penetration attacks. Organizations using up-imapproxy in their email infrastructure face significant risk, particularly in environments where the proxy acts as a gateway between internal networks and external IMAP servers.
Security practitioners should implement immediate mitigations including updating to patched versions of up-imapproxy, applying firewall rules to restrict IMAP traffic to trusted sources, and implementing network segmentation to limit the impact of potential exploitation. The vulnerability aligns with CWE-134, which specifically addresses the use of format strings inappropriately, and maps to ATT&CK technique T1059.007 for remote code execution through vulnerable applications. Additionally, organizations should conduct comprehensive network scans to identify affected systems and implement monitoring for unusual IMAP traffic patterns that might indicate exploitation attempts. The flaw underscores the importance of input validation and secure coding practices, particularly when handling untrusted data in applications that process network communications.