CVE-2012-0870 in BlackBerry PlayBook tablet
Summary
by MITRE
Heap-based buffer overflow in process.c in smbd in Samba 3.0, as used in the file-sharing service on the BlackBerry PlayBook tablet before 2.0.0.7971 and other products, allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via a Batched (aka AndX) request that triggers infinite recursion.
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Analysis
by VulDB Data Team • 11/30/2021
The vulnerability identified as CVE-2012-0870 represents a critical heap-based buffer overflow flaw within the Samba file-sharing service implementation, specifically affecting the smbd daemon component. This vulnerability exists in Samba version 3.0 and impacts the BlackBerry PlayBook tablet operating system prior to version 2.0.0.7971, along with other affected products that utilize this version of the Samba software stack. The flaw manifests in the process.c file which handles batched requests, creating a dangerous condition that can be exploited by remote attackers to compromise system integrity.
The technical exploitation of this vulnerability occurs through a specific type of request known as Batched or AndX requests that are processed by the Samba server. When these particular requests are sent to the affected system, they trigger an infinite recursion pattern within the memory management routines of the smbd daemon. This infinite recursion leads to excessive heap memory consumption and ultimately results in a buffer overflow condition where the program attempts to write data beyond the allocated memory boundaries. The heap-based nature of this vulnerability means that the overflow occurs in dynamically allocated memory regions rather than stack memory, making it particularly challenging to detect and exploit reliably.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enabling remote code execution capabilities. While the primary effect is a daemon crash that causes service disruption, the buffer overflow condition creates opportunities for attackers to inject malicious code into the vulnerable process memory space. This represents a significant security risk as it allows attackers to potentially gain unauthorized control over the file-sharing service, leading to data compromise, privilege escalation, or complete system takeover depending on the execution context. The vulnerability affects the core file-sharing functionality of the affected systems, making it particularly dangerous in enterprise environments where file access and sharing are critical operations.
The root cause of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions that occur when a program writes more data to a heap-allocated buffer than it can hold. This flaw demonstrates poor input validation and inadequate memory boundary checking in the processing of batched requests. From an adversarial perspective, this vulnerability maps to several ATT&CK techniques including T1210 for exploitation of remote services and T1059 for command and control through file sharing protocols. The vulnerability's exploitation requires minimal privileges since it targets the service daemon itself, making it particularly attractive to attackers seeking to establish persistent access to networked systems. Organizations should prioritize patching this vulnerability immediately, as the combination of remote exploitability and potential code execution capabilities makes it a high-priority threat requiring immediate remediation.
Mitigation strategies should include immediate deployment of vendor patches and updates to Samba version 3.0 and subsequent releases that address the infinite recursion condition in batched request processing. Network segmentation and access control measures should be implemented to limit exposure of affected systems to untrusted networks, while monitoring systems should be configured to detect unusual patterns in SMB traffic that might indicate exploitation attempts. Additionally, implementing intrusion detection systems with signature-based detection for known patterns of this vulnerability can help identify and block exploitation attempts before they can cause damage to the affected systems.