CVE-2021-46749 is a high-severity vulnerability that arises from insufficient bounds checking in the AMD Secure Processor (ASP). This flaw may allow for an out-of-bounds read in the System Management Interface (SMI) mailbox checksum calculation, which can trigger a data abort, ultimately leading to a potential denial of service.
The vulnerability has a CVSS score of 7.5, classifying it as high severity. Such vulnerabilities are critical as they can be exploited over the network with low attack complexity and no privileges required, making them particularly dangerous in real-world scenarios.
Risk to organizations includes potential service interruptions, which can disrupt operations and impact business continuity. Therefore, organizations utilizing affected AMD firmware should prioritize remediation measures.
Given the urgency associated with this vulnerability, organizations should address it in their priority patch cycle. The vulnerability was published on May 9, 2023, and has been marked as modified since its initial disclosure.
Vulnerability Details
The CVE description indicates that the vulnerability results from insufficient bounds checking within the AMD Secure Processor, specifically in the SMI mailbox checksum calculation process. The improper handling of bounds can lead to a denial of service due to data aborts.
The CVSS 3.1 vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, which indicates a network attack vector, low attack complexity, no privileges required, and high availability impact. The affected systems include several firmware versions for AMD Ryzen and Athlon processors.
Technical Analysis
The root cause of CVE-2021-46749 lies in the insufficient checking of bounds when processing data in the SMI mailbox. This lack of rigorous validation allows attackers to exploit the vulnerability, leading to potential service disruptions.
The attack vector is network-based, meaning that an attacker could exploit this vulnerability remotely without any physical access to the target system. The attack complexity is classified as low, indicating that it could be executed with minimal effort.
No user interaction is required for the attack to be successful, which escalates the risk. The availability impact is high, which means that successful exploitation could lead to significant operational downtime.
Risk & Impact Analysis
The real-world risk associated with CVE-2021-46749 is substantial, given its potential to cause denial of service. Organizations running affected AMD firmware must assess their exposure and implement necessary changes to ensure service availability.
The blast radius of this vulnerability could extend to all systems utilizing the vulnerable firmware versions, impacting numerous users and operations. The urgency for remediation is high, as organizations should prioritize patching to mitigate the risks posed by this vulnerability.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions prior to vendor patch are affected, specifically the firmware versions for AMD Ryzen and Athlon processors, including Ryzen 5300G, 5300GE, 5500, 5600, and others.
Mitigation & Remediation
Organizations should prioritize patching immediately. AMD has released updates to address this vulnerability, and organizations should ensure they are running the latest firmware versions.
For those unable to apply patches immediately, implementing configuration hardening and network controls may help mitigate risks. Continuous monitoring for any anomalous behavior is also recommended.
Detection Guidance
Organizations should monitor logs for indicators of compromise related to this vulnerability, including unexpected service interruptions and abnormal SMI operations. Behavioral anomalies, such as unauthorized access attempts or unusual system crashes, should also be investigated.
AppSecure Threat Intelligence Insight
CVE-2021-46749 exemplifies the ongoing challenges in secure processor design and highlights the importance of rigorous bounds checking. Security teams should learn from this vulnerability to enhance their threat modeling and defensive strategies.
By integrating lessons learned from vulnerabilities into security assessments, organizations can better prepare for similar issues. Continuous security testing and penetration testing methodologies are critical in identifying these kinds of vulnerabilities before they can be exploited.
Penetration testing should be a standard practice to validate the security posture of firmware and other critical systems.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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