CVE-2004-0883 in Linux
Summary
by MITRE
Multiple vulnerabilities in the samba filesystem (smbfs) in Linux kernel 2.4 and 2.6 allow remote samba servers to cause a denial of service (crash) or gain sensitive information from kernel memory via a samba server (1) returning more data than requested to the smb_proc_read function, (2) returning a data offset from outside the samba packet to the smb_proc_readX function, (3) sending a certain TRANS2 fragmented packet to the smb_receive_trans2 function, (4) sending a samba packet with a certain header size to the smb_proc_readX_data function, or (5) sending a certain packet based offset for the data in a packet to the smb_receive_trans2 function.
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Analysis
by VulDB Data Team • 12/16/2024
The vulnerability described in CVE-2004-0883 represents a critical class of issues affecting the Linux kernel's SMB filesystem implementation, specifically within the smbfs module that facilitates communication with samba servers. This vulnerability impacts kernel versions 2.4 and 2.6, exposing systems to potential denial of service conditions and information disclosure risks. The flaw stems from inadequate input validation and buffer handling within several key functions responsible for processing samba protocol packets, creating multiple attack vectors that can be exploited by remote samba servers to compromise system stability and potentially extract sensitive kernel memory information. The vulnerability operates at the kernel level, making it particularly dangerous as it can affect the fundamental operating system functionality and potentially provide attackers with privileged access to system resources.
The technical implementation of this vulnerability involves several distinct attack vectors that exploit different functions within the smbfs subsystem. The first vector occurs when a samba server returns more data than requested to the smb_proc_read function, causing buffer overflows or memory corruption that can lead to kernel crashes. The second vector involves returning a data offset from outside the samba packet to the smb_proc_readX function, which can result in reading invalid memory locations and potentially exposing kernel memory contents. The third vulnerability manifests through TRANS2 fragmented packet handling in the smb_receive_trans2 function, where malformed packet structures can cause memory corruption during packet reassembly. The fourth and fifth vectors involve specific header size manipulations and data offset handling in the smb_proc_readX_data and smb_receive_trans2 functions respectively, all of which can trigger similar memory corruption issues. These vulnerabilities collectively represent a series of insufficient boundary checks and improper memory management practices that allow malicious samba servers to manipulate kernel memory structures.
The operational impact of CVE-2004-0883 extends beyond simple denial of service conditions to include potential information disclosure and system instability. When exploited, these vulnerabilities can cause kernel crashes that result in complete system downtime, forcing administrators to reboot affected systems and potentially losing unsaved data. The information disclosure aspect presents additional security concerns as attackers may be able to extract sensitive kernel memory contents, which could include credentials, system configuration details, or other privileged information. This vulnerability particularly affects systems that rely on samba file sharing protocols, making it relevant to networked environments where file sharing and remote access are common requirements. The remote nature of the attack means that systems do not need to be physically compromised to be affected, as the vulnerability can be triggered through network communication with malicious samba servers.
Mitigation strategies for CVE-2004-0883 should focus on both immediate patching and network-level protections. The primary solution involves applying kernel updates that address the specific buffer overflow and memory handling issues in the smbfs module, which typically include enhanced input validation and proper boundary checking in the affected functions. System administrators should also implement network segmentation to limit access to samba services and consider disabling smbfs functionality if it is not essential for operations. Additional protective measures include monitoring network traffic for suspicious samba packet patterns and implementing intrusion detection systems that can identify potential exploitation attempts. From a security standards perspective, this vulnerability aligns with CWE-129, which covers insufficient validation of length of inputs, and CWE-125, which addresses out-of-bounds read conditions. The attack vectors described in this vulnerability map to ATT&CK techniques including T1059 for command and scripting interpreter and T1499 for endpoint disruption, as the vulnerability enables both system instability and potential privilege escalation through information disclosure. Organizations should also consider implementing kernel hardening measures such as stack canaries and address space layout randomization to reduce the effectiveness of potential exploitation attempts.