Source: cve@mitre.org
Buffer overflow in Entrust LibKmp ISAKMP library, as used by Symantec Enterprise Firewall 7.0 through 8.0, Gateway Security 5300 1.0, Gateway Security 5400 2.0, and VelociRaptor 1.5, allows remote attackers to execute arbitrary code via a crafted ISAKMP payload.
Critical vulnerability exists in the Entrust LibKmp ISAKMP library, impacting several Symantec and VelociRaptor firewall products. This remote code execution (RCE) vulnerability allows attackers to gain complete control of vulnerable systems by sending a crafted ISAKMP payload, potentially leading to data breaches and system compromise.
Step 1: Payload Delivery: The attacker sends a malicious ISAKMP packet to a vulnerable firewall. This packet is crafted to contain an ISAKMP payload designed to trigger the buffer overflow.
Step 2: Packet Reception and Processing: The firewall's ISAKMP library (Entrust LibKmp) receives and attempts to process the malicious packet.
Step 3: Buffer Overflow Trigger: The library attempts to copy the attacker-supplied payload data into a fixed-size buffer. Due to the lack of size validation, the copy operation writes beyond the buffer's boundaries, causing a buffer overflow.
Step 4: Code Execution Control: The overflow overwrites critical memory regions, such as the return address on the stack. This allows the attacker to control the program's execution flow.
Step 5: Arbitrary Code Execution: The attacker's crafted payload includes shellcode or a pointer to shellcode. When the program returns from the function containing the overflow, it jumps to the attacker-controlled address, executing the attacker's code and achieving RCE.
The vulnerability is a buffer overflow within the Entrust LibKmp ISAKMP library. The flaw lies in how the library handles ISAKMP payloads. Specifically, the code fails to properly validate the size of data received within an ISAKMP packet before copying it into a fixed-size buffer. This allows an attacker to send a specially crafted packet containing more data than the buffer can hold, leading to a buffer overflow. This overwrites adjacent memory, potentially corrupting critical program data or overwriting the return address on the stack. By controlling the overwritten data, an attacker can redirect program execution to arbitrary code, achieving remote code execution (RCE). The root cause is a lack of bounds checking on the input data size before the copy operation.
While no specific APT groups are definitively linked to this specific CVE, the nature of the vulnerability (RCE) makes it attractive to a wide range of threat actors. This type of vulnerability is often leveraged by groups seeking initial access or persistence. The age of the vulnerability suggests it may be used by less sophisticated actors as well. This vulnerability is not listed on the CISA KEV at the time of this report.
Network Intrusion Detection Systems (NIDS) can be configured to detect malicious ISAKMP packets with oversized payloads or specific patterns associated with known exploits.
Security Information and Event Management (SIEM) systems can be configured to analyze firewall logs for suspicious ISAKMP traffic, including unusual packet sizes or frequent connection attempts.
Host-based Intrusion Detection Systems (HIDS) can monitor for unusual process behavior or memory corruption on the firewall.
Forensic analysis of firewall logs and memory dumps can reveal evidence of a buffer overflow, such as overwritten memory regions or the execution of unexpected code.
Apply security patches provided by the vendor. This is the most effective remediation.
If patching is not immediately possible, implement network segmentation to limit the impact of a successful exploit. Isolate vulnerable firewalls from critical internal networks.
Implement a Web Application Firewall (WAF) or other network security devices that can inspect and filter ISAKMP traffic.
Regularly review and update security policies and configurations for all network devices.
Conduct vulnerability scans to identify and prioritize patching efforts.
Implement a robust incident response plan to address potential exploitation attempts.