CVE-2007-2491 in Server
Summary
by MITRE
The PIIX4 power management subsystem in EMC VMware Workstation 5.5.3.34685 and VMware Server 1.0.1.29996 allows local users to write to arbitrary memory locations via a crafted poke to I/O port 0x1004, triggering a denial of service (virtual machine crash) or other unspecified impact, a related issue to CVE-2007-1337.
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Analysis
by VulDB Data Team • 03/12/2017
The vulnerability described in CVE-2007-2491 represents a critical security flaw within the PIIX4 power management subsystem of VMware Workstation 5.5.3.34685 and VMware Server 1.0.1.29996. This issue stems from improper input validation and memory management within the virtualization environment's hardware emulation layer. The vulnerability specifically affects the power management functionality that emulates the PIIX4 chipset's power management controller, which is essential for proper virtual machine operation and system power states. The flaw manifests when local users exploit a crafted poke to I/O port 0x1004, which bypasses normal access controls and allows arbitrary memory writes. This vulnerability operates at the virtual machine monitor level where guest operating systems can potentially interact with host system resources through emulated hardware components, creating a dangerous attack surface for privilege escalation and system compromise.
The technical implementation of this vulnerability involves the manipulation of I/O port 0x1004 which serves as a communication channel between the virtual machine and the emulated PIIX4 power management controller. When an attacker sends malformed data to this specific port, the virtualization software fails to properly validate the memory addresses being written to, allowing direct memory manipulation without proper authorization checks. The flaw essentially creates a write-what-where primitive that can be exploited to overwrite critical memory locations within the VMware hypervisor process. This type of vulnerability falls under CWE-787 which describes "Out-of-bounds Write" conditions where an application writes data past the boundaries of a buffer or memory location. The vulnerability demonstrates a classic case of insufficient input sanitization and improper privilege boundary enforcement within the virtualization layer, where guest operating systems should not have direct access to host memory management functions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios as initially described. While the primary effect results in virtual machine crashes and system instability, the underlying memory corruption capabilities could potentially enable more sophisticated attacks. Attackers could leverage this vulnerability to corrupt critical hypervisor data structures, leading to complete system compromise or privilege escalation. The vulnerability's relationship to CVE-2007-1337 indicates a broader pattern of flaws within VMware's power management emulation, suggesting that similar issues may exist in other components of the virtualization stack. This vulnerability represents a significant concern for enterprise environments where VMware products are extensively deployed, as local users with access to virtual machines could potentially leverage this flaw to gain unauthorized access to the host system. The attack requires local access within the guest operating system but could be particularly dangerous in multi-tenant environments where guest isolation is critical for security.
Mitigation strategies for this vulnerability require immediate patching of affected VMware products to address the memory validation issues in the PIIX4 power management subsystem. Organizations should implement strict access controls and monitor for unauthorized I/O port activity within virtual machines. The vulnerability aligns with ATT&CK technique T1059 which describes command and scripting interpreter usage, as attackers may attempt to exploit this vulnerability through system-level commands that interact with I/O ports. Additionally, implementing virtual machine isolation measures and disabling unnecessary hardware emulation features can reduce the attack surface. System administrators should also consider implementing memory protection mechanisms and regular security audits to detect potential exploitation attempts. The vulnerability highlights the importance of proper privilege separation in virtualization environments and the need for comprehensive input validation across all emulated hardware components. Organizations should also establish incident response procedures specifically for virtualization-related security incidents and ensure that all virtualization platforms are kept up to date with the latest security patches.