CVE-2007-5007 in balsa
Summary
by MITRE
Stack-based buffer overflow in the ir_fetch_seq function in balsa before 2.3.20 might allow remote IMAP servers to execute arbitrary code via a long response to a FETCH command.
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Analysis
by VulDB Data Team • 07/29/2019
The vulnerability identified as CVE-2007-5007 represents a critical stack-based buffer overflow flaw within the balsa email client software. This vulnerability specifically affects versions prior to 2.3.20 and resides within the ir_fetch_seq function that handles IMAP protocol communication. The flaw occurs when the software processes a malformed response from an IMAP server during a FETCH command operation, creating an exploitable condition that could enable remote code execution.
The technical implementation of this vulnerability stems from inadequate input validation within the ir_fetch_seq function which fails to properly bounds-check data received from IMAP servers. When a remote IMAP server sends an excessively long response to a FETCH command, the balsa client's stack buffer cannot accommodate the overflow data, causing adjacent memory locations to be overwritten. This classic buffer overflow scenario allows an attacker to manipulate the program's execution flow by overwriting return addresses and potentially injecting malicious code into the stack memory space.
From an operational perspective, this vulnerability presents a significant risk to email server security and user privacy since it enables remote exploitation without requiring authentication. An attacker controlling an IMAP server could craft malicious responses that trigger the buffer overflow when a user accesses their email through the vulnerable balsa client. The implications extend beyond simple code execution to potential complete system compromise, as successful exploitation could lead to unauthorized access to user mailboxes, data exfiltration, and persistent backdoor installation. This vulnerability particularly affects organizations relying on balsa as their primary email client software, making it a prime target for advanced persistent threats.
The vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified under the Common Weakness Enumeration framework for software security flaws. From an adversary tactics perspective, this vulnerability aligns with ATT&CK technique T1190 for Exploit Public-Facing Application, as it represents an attack surface that can be exploited through network-based communication protocols. The attack vector requires network access to the target IMAP server and successful delivery of a specially crafted response that triggers the vulnerable code path. Mitigation strategies should include immediate deployment of the patched balsa version 2.3.20 or later, implementation of network-based intrusion detection systems to monitor for suspicious IMAP traffic patterns, and consideration of network segmentation to limit exposure of email clients to untrusted IMAP servers. Additionally, administrators should implement strict input validation policies and consider deploying email client software with more robust memory management practices to prevent similar vulnerabilities from occurring in other components of the email infrastructure.