CVE-2012-3417 in Linux DiskQuota
Summary
by MITRE
The good_client function in rquotad (rquota_svc.c) in Linux DiskQuota (aka quota) before 3.17 invokes the hosts_ctl function the first time without a host name, which might allow remote attackers to bypass TCP Wrappers rules in hosts.deny.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2012-3417 resides within the Linux DiskQuota system's rquotad daemon, specifically in the good_client function located in rquota_svc.c. This flaw represents a significant security weakness that affects versions of the quota package prior to 3.17, creating an avenue for remote attackers to circumvent access control mechanisms that should otherwise protect system resources. The issue stems from the improper invocation of the hosts_ctl function during the initial call to the good_client function, which occurs without providing a host name parameter.
The technical implementation of this vulnerability involves the rquotad daemon's handling of client connections where the hosts_ctl function is called without proper host identification during the first invocation. This omission creates a window where TCP Wrappers rules defined in hosts.deny and hosts.allow files can be bypassed, allowing unauthorized access to quota services that should be restricted based on host-based access control policies. The hosts_ctl function typically validates client connections against access control lists, but when called without a host name parameter, it cannot properly evaluate the connection against configured rules, effectively neutralizing the security controls that administrators have put in place.
From an operational perspective, this vulnerability enables remote attackers to gain unauthorized access to disk quota services without being properly authenticated or authorized through standard TCP Wrappers mechanisms. The impact extends beyond simple access bypass as it undermines the fundamental security model of host-based access control that many organizations rely upon for network segmentation and service protection. Attackers could exploit this weakness to access quota information, potentially gaining insights into disk usage patterns, user account details, or even manipulating quota configurations in ways that could affect system stability and resource allocation.
The vulnerability aligns with CWE-284, which addresses improper access control, and represents a classic example of how improper function parameter handling can lead to security bypasses. From an ATT&CK framework perspective, this issue maps to TA0001 Initial Access and TA0006 Credential Access, as it provides a method for attackers to establish unauthorized access to system services and potentially escalate privileges through information gathering. Organizations implementing TCP Wrappers for service access control are particularly at risk, as the vulnerability effectively nullifies the protection provided by these mechanisms.
Mitigation strategies for CVE-2012-3417 primarily involve upgrading to Linux DiskQuota version 3.17 or later, where the implementation has been corrected to properly pass host name parameters to the hosts_ctl function. Administrators should also review and validate their TCP Wrappers configurations to ensure that alternative access control measures are in place, such as firewall rules, network segmentation, or additional authentication mechanisms. Additionally, monitoring for unauthorized access attempts to quota services should be implemented, as this vulnerability could potentially be used as a stepping stone for more extensive attacks against the system or network infrastructure.