CVE-2018-14353 in Mutt
Summary
by MITRE
An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap_quote_string in imap/util.c has an integer underflow.
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Analysis
by VulDB Data Team • 04/09/2023
The vulnerability identified as CVE-2018-14353 represents a critical integer underflow condition within the IMAP client functionality of Mutt and NeoMutt email clients. This flaw exists in the imap_quote_string function located in the imap/util.c source file, affecting versions prior to 1.10.1 for Mutt and 2018-07-16 for NeoMutt. The integer underflow occurs when processing IMAP string quoting operations, creating a scenario where an attacker can manipulate input data to cause unexpected behavior in the application's memory handling mechanisms. This vulnerability specifically impacts the secure processing of IMAP protocol communications, which are fundamental to email client operations when connecting to remote mail servers.
The technical exploitation of this integer underflow stems from improper input validation and boundary checking within the IMAP utility functions that handle string quoting operations. When the imap_quote_string function processes certain input parameters, it fails to properly validate the size or length constraints of the data being quoted, leading to an arithmetic underflow condition where a signed integer becomes negative when it should remain positive. This condition can result in memory corruption, buffer overflows, or other undefined behaviors that may be exploited by malicious actors to execute arbitrary code or cause denial of service conditions. The flaw operates at the protocol level where email clients communicate with IMAP servers, making it particularly dangerous as it can be triggered through normal email operations such as message retrieval or folder synchronization.
The operational impact of CVE-2018-14353 extends beyond simple denial of service scenarios to potentially enable remote code execution in vulnerable configurations. Attackers can leverage this vulnerability by crafting specially formatted IMAP responses or commands that trigger the underflow condition during string processing. This creates opportunities for privilege escalation, data exfiltration, or complete system compromise when email clients process maliciously crafted messages or server responses. The vulnerability affects organizations relying on Mutt or NeoMutt for email management, particularly those using IMAP protocols for accessing corporate or personal mailboxes. Security researchers have classified this as a high-severity issue due to its potential for remote exploitation and the widespread use of these email clients in enterprise environments.
Mitigation strategies for CVE-2018-14353 primarily focus on immediate software updates to versions that contain the patched implementation of the imap_quote_string function. System administrators should prioritize updating to Mutt 1.10.1 or NeoMutt versions released after 2018-07-16, which contain the necessary fixes for the integer underflow condition. Additionally, organizations should implement network segmentation and access controls to limit exposure of email clients to untrusted IMAP servers or malicious actors. Security monitoring should include detection of unusual IMAP traffic patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-191, which describes integer underflow conditions, and can be mapped to ATT&CK technique T1203 for exploitation of remote services. Organizations should also consider implementing email content filtering and sandboxing mechanisms to reduce the risk of exploitation through malicious email attachments or crafted IMAP responses. The fix typically involves proper input validation and boundary checking to prevent the integer arithmetic from producing negative results in contexts where only positive values are expected.