CVE-2020-11520 in SecureDoc
Summary
by MITRE
The SDDisk2k.sys driver of WinMagic SecureDoc v8.5 and earlier allows local users to write to arbitrary kernel memory addresses because the IOCTL dispatcher lacks pointer validation. Exploiting this vulnerability results in privileged code execution.
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Analysis
by VulDB Data Team • 10/26/2020
The vulnerability identified as CVE-2020-11520 resides within the SDDisk2k.sys kernel driver component of WinMagic SecureDoc version 8.5 and earlier. This driver serves as a critical element in the encryption and disk management functionality of the software, handling low-level system operations that require elevated privileges. The flaw manifests in the driver's IOCTL (Input/Output Control) dispatcher mechanism, which processes commands sent from user-mode applications to the kernel-mode driver. The vulnerability stems from inadequate validation of user-supplied pointers, creating a path for malicious code execution through kernel memory manipulation. This type of vulnerability represents a classic example of improper input validation, which falls under the CWE-707 category of "Improper Neutralization of Input During Web Page Generation" but in kernel space context.
The technical exploitation of this vulnerability occurs when a local attacker crafts a malicious IOCTL request containing a specially formatted pointer that points to arbitrary kernel memory addresses. Without proper validation, the driver accepts this pointer and proceeds to write data to the specified memory location, effectively allowing arbitrary kernel memory modification. This flaw creates a privilege escalation vector that transforms a local user account into a kernel-level privileged process. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, specifically targeting the kernel through driver vulnerabilities. The vulnerability's impact extends beyond simple code execution as it allows attackers to modify critical kernel structures, potentially leading to complete system compromise and persistent access.
The operational implications of CVE-2020-11520 are severe for organizations relying on WinMagic SecureDoc for disk encryption and data protection. Local attackers who can execute code on a target system gain the ability to escalate privileges to kernel level, bypassing standard operating system security controls. This vulnerability undermines the very foundation of system security that disk encryption software is designed to provide, as attackers can manipulate the encryption driver itself to gain unauthorized access to protected data. The exploitability requires local system access but does not require network connectivity, making it particularly dangerous in environments where physical or local access is possible. Organizations using affected versions of SecureDoc face potential data breaches, system compromise, and complete loss of encryption integrity, as the attacker can modify the driver's behavior to disable or bypass encryption mechanisms.
Mitigation strategies for CVE-2020-11520 focus primarily on patching the vulnerable driver component through updates provided by WinMagic. Organizations should immediately upgrade to WinMagic SecureDoc versions that have addressed this vulnerability, as the vendor has released patches to implement proper pointer validation in the IOCTL dispatcher. System administrators should also implement additional security measures including restricting local user access to systems running affected software, monitoring for suspicious IOCTL activity, and ensuring that only trusted applications can interact with the vulnerable driver. The principle of least privilege should be enforced by limiting access to the SecureDoc driver and monitoring for unauthorized kernel memory modifications. Additionally, organizations should consider implementing kernel-mode exploit detection mechanisms and maintaining comprehensive system monitoring to identify potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable driver in the environment, as this vulnerability can persist across multiple systems if not properly patched.