CVE-2018-14362 in Mutt
Summary
by MITRE
An issue was discovered in Mutt before 1.10.1 and NeoMutt before 2018-07-16. pop.c does not forbid characters that may have unsafe interaction with message-cache pathnames, as demonstrated by a '/' character.
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Analysis
by VulDB Data Team • 04/09/2023
The vulnerability identified as CVE-2018-14362 represents a path traversal flaw in the Mutt email client software that affects versions prior to 1.10.1 and NeoMutt versions before 2018-07-16. This issue resides within the pop.c component of the email client's codebase, specifically concerning how it handles message-cache pathnames during POP3 protocol operations. The flaw stems from insufficient input validation and sanitization of characters that are permitted in message identifiers or cache filenames, creating a potential security risk that could be exploited by malicious actors.
The technical implementation of this vulnerability occurs when Mutt processes email messages retrieved via POP3 protocol and stores them in a message cache directory. The pop.c module fails to properly sanitize or reject certain characters that could be interpreted as path separators or traversal operators within the file system. Most notably, the forward slash character '/' is not adequately filtered, allowing attackers to manipulate cache pathname generation through crafted message identifiers or headers. This vulnerability directly relates to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The operational impact of this vulnerability extends beyond simple file system manipulation, as it could potentially allow attackers to create arbitrary files in unintended locations or even overwrite existing files within the message cache directory structure. When an attacker controls the content of email messages or can influence message identifiers, they may be able to construct cache filenames that traverse directories and access sensitive areas of the file system. This could lead to privilege escalation, data corruption, or unauthorized file access depending on the system configuration and the privileges under which the email client operates. The vulnerability is particularly concerning in multi-user environments or when Mutt is executed with elevated privileges.
The attack vector for this vulnerability typically involves an attacker sending specially crafted email messages to a victim who uses the vulnerable Mutt or NeoMutt client. The attacker must be able to influence the message identifiers or headers that are used to generate cache filenames, which is often possible when the victim receives emails from untrusted sources. Mitigation strategies include upgrading to patched versions of Mutt (1.10.1 or later) or NeoMutt (2018-07-16 or later) where the pop.c component properly sanitizes input characters. System administrators should also implement proper access controls and file system permissions to limit the impact of any potential exploitation, while network administrators can consider implementing email filtering rules to detect and block suspicious email content that might attempt to exploit such vulnerabilities. The fix typically involves implementing character filtering or sanitization routines that prevent path traversal characters from being used in cache pathname generation, aligning with ATT&CK technique T1059.007 for command and scripting interpreter.