CVE-2018-14358 in Mutt
Summary
by MITRE
An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. imap/message.c has a stack-based buffer overflow for a FETCH response with a long RFC822.SIZE field.
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Analysis
by VulDB Data Team • 04/09/2023
The vulnerability identified as CVE-2018-14358 represents a critical stack-based buffer overflow flaw in the Mutt email client software family, affecting versions prior to 1.10.1 and NeoMutt versions before the 2018-07-16 release. This issue specifically manifests within the imap/message.c component of the software, where improper handling of FETCH responses containing excessively long RFC822.SIZE fields creates a condition that allows attackers to overwrite adjacent memory locations on the stack. The vulnerability stems from insufficient input validation and bounds checking when processing IMAP protocol responses, particularly those related to message size information. The RFC822.SIZE field in IMAP FETCH responses is designed to provide the size of email messages in octets, but the Mutt implementation fails to properly validate the length of this field before copying it into a fixed-size buffer on the stack.
The technical exploitation of this vulnerability occurs when a malicious IMAP server or man-in-the-middle attacker crafts a FETCH response with an abnormally large RFC822.SIZE value that exceeds the allocated buffer space. When Mutt processes this malformed response, the buffer overflow can overwrite adjacent stack variables, potentially leading to arbitrary code execution or application crash. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in the CWE top 25 most dangerous software weaknesses. The attack vector is primarily through network-based IMAP connections, making it particularly concerning for email clients that frequently connect to remote mail servers. The vulnerability demonstrates characteristics consistent with the ATT&CK technique T1059.007 for Command and Scripting Interpreter: Python, though in this case the exploitation involves memory corruption rather than direct scripting.
The operational impact of this vulnerability extends beyond simple application instability, as successful exploitation could enable attackers to execute arbitrary code with the privileges of the Mutt process. This poses significant risks to users who rely on Mutt for email processing, particularly in enterprise environments where email clients may have elevated privileges or access to sensitive data. The vulnerability affects not only individual users but also organizations that deploy Mutt as part of their email infrastructure, potentially creating persistent security risks. Attackers could leverage this vulnerability to gain unauthorized access to email communications, potentially accessing confidential information or using the compromised client as a pivot point for further attacks within a network. The issue is particularly dangerous because it requires minimal user interaction beyond connecting to a malicious IMAP server, making it a stealthy and effective attack vector. Organizations using affected versions of Mutt should consider immediate remediation through version updates, as the vulnerability has been widely recognized and patched in subsequent releases. The fix typically involves implementing proper bounds checking on the RFC822.SIZE field values and ensuring that buffer allocations accommodate potential maximum field lengths. Additionally, network monitoring and intrusion detection systems should be configured to detect unusual IMAP traffic patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the importance of input validation in network protocols and the critical need for regular security updates in email client software.