CVE-2018-6787 in Jiangmin
Summary
by MITRE
In Jiangmin Antivirus 16.0.0.100, the driver file (KVFG.sys) allows local users to cause a denial of service (BSOD) or possibly have unspecified other impact because of not validating input values from IOCtl 0x221808.
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Analysis
by VulDB Data Team • 01/02/2020
The vulnerability identified as CVE-2018-6787 affects Jiangmin Antivirus version 16.0.0.100 and represents a critical security flaw within the kernel-mode driver component KVFG.sys. This issue arises from insufficient input validation mechanisms within the driver's implementation of the IOCTL 0x221808 control code, creating a pathway for local privilege escalation and system instability. The vulnerability exists at the intersection of kernel-level security controls and improper validation of user-supplied data, making it particularly dangerous as it can be exploited by any local user with access to the system.
The technical implementation of this flaw demonstrates a classic buffer overflow or input validation weakness where the driver fails to properly sanitize or validate data received through the IOCTL interface. When a local user sends crafted input data to the KVFG.sys driver via the specific IOCTL code 0x221808, the driver processes this data without adequate checks, potentially leading to memory corruption or invalid memory access patterns. This type of vulnerability falls under CWE-125: Out-of-bounds Read and CWE-787: Out-of-bounds Write, representing the fundamental failure to validate input parameters before processing them within kernel space. The lack of proper bounds checking allows malicious input to overwrite critical memory locations or trigger invalid memory access exceptions that result in system crashes.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can potentially enable more severe consequences including system instability and privilege escalation. When the driver encounters malformed input data, it may trigger a Blue Screen of Death (BSOD) due to kernel memory corruption, effectively causing a system crash that disrupts normal operations. The unspecified other impacts mentioned in the vulnerability description suggest that under certain conditions, this flaw could potentially allow local users to escalate privileges or execute arbitrary code within the kernel context. This represents a significant threat to system integrity and could be leveraged by attackers to gain elevated privileges or establish persistent access to compromised systems. The ATT&CK framework categorizes this vulnerability under T1068: Exploitation for Privilege Escalation and T1490: Inhibit System Recovery, highlighting its potential for both immediate system disruption and longer-term compromise.
Mitigation strategies for CVE-2018-6787 should focus on immediate patching and system hardening measures. Organizations must prioritize updating to the latest version of Jiangmin Antivirus that addresses this specific driver vulnerability, as the manufacturer has likely released a patched version of the KVFG.sys driver with proper input validation mechanisms. System administrators should also implement additional monitoring and logging of IOCTL activity to detect potential exploitation attempts, while applying the principle of least privilege to limit local user access. The vulnerability underscores the importance of kernel-mode security testing and input validation, particularly for security software that operates with elevated privileges. Regular security assessments of antivirus driver components should be conducted to identify similar validation gaps, and system administrators should consider implementing additional security controls such as driver signature enforcement and kernel-mode protection mechanisms to prevent exploitation of similar vulnerabilities.