CVE-2015-7236 in Solaris
Summary
by MITRE
Use-after-free vulnerability in xprt_set_caller in rpcb_svc_com.c in rpcbind 0.2.1 and earlier allows remote attackers to cause a denial of service (daemon crash) via crafted packets, involving a PMAP_CALLIT code.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/26/2022
The CVE-2015-7236 vulnerability represents a critical use-after-free flaw in the rpcbind service daemon that affects versions 0.2.1 and earlier. This vulnerability specifically resides in the xprt_set_caller function within the rpcb_svc_com.c source file, making it a fundamental component of the remote procedure call binding service that handles network communication for distributed applications. The rpcbind service operates as a crucial middleware component that maps RPC program numbers to network addresses, enabling client applications to locate and communicate with RPC servers across network boundaries. When attackers exploit this vulnerability through crafted packets containing PMAP_CALLIT code, they can manipulate the service daemon into executing invalid memory operations that lead to system instability and complete service disruption.
The technical nature of this vulnerability stems from improper memory management within the rpcbind daemon's handling of network transport connections. When the xprt_set_caller function processes incoming RPC calls with PMAP_CALLIT operations, it fails to properly validate or sanitize the memory references associated with the transport layer connections. This memory management error creates a scenario where freed memory blocks are accessed after being deallocated, leading to undefined behavior and potential crash conditions. The vulnerability specifically impacts the daemon's ability to maintain proper state management during concurrent network operations, where multiple connection handlers may attempt to access the same memory location after it has been released by another process thread. This flaw falls under the CWE-416 category of Use After Free, which is classified as a serious memory corruption vulnerability that can lead to arbitrary code execution or denial of service conditions.
The operational impact of CVE-2015-7236 extends beyond simple service disruption to potentially compromise entire network infrastructure dependencies. Since rpcbind serves as a foundational service for RPC-based applications across Unix and Linux systems, attackers can leverage this vulnerability to cause cascading failures in distributed computing environments. The remote exploitation capability means that adversaries do not require local system access or credentials to trigger the vulnerability, making it particularly dangerous for network-facing systems. When the daemon crashes due to this memory corruption, it can result in complete service unavailability for legitimate users attempting to access RPC services, leading to business disruption and potential data access limitations. The vulnerability's exploitation can also be automated through network scanning tools, making it attractive to threat actors seeking to establish persistent denial of service conditions against targeted organizations.
Mitigation strategies for CVE-2015-7236 should prioritize immediate patching of affected rpcbind installations to versions 0.2.2 or later where the memory management issues have been addressed. System administrators must implement network segmentation and access controls to limit exposure of rpcbind services to untrusted networks, particularly by restricting access to the standard RPC port 111 and related service ports. Network monitoring solutions should be configured to detect unusual traffic patterns or malformed packets that may indicate exploitation attempts targeting this vulnerability. Additionally, implementing intrusion detection systems with signature-based detection for PMAP_CALLIT operations can help identify potential attack vectors. The vulnerability demonstrates the importance of proper memory management in daemon processes and highlights the need for thorough code review and testing of network services that handle external input. Organizations should also consider implementing service-level redundancy and failover mechanisms to maintain availability during potential exploitation events, as the vulnerability can be leveraged for both disruptive denial of service attacks and potentially more sophisticated exploitation attempts that could lead to system compromise.