CVE-2022-38692: Critical RSA Key Size Validation Vulnerability in BootROM

Overview

BootROM, a fundamental component in many computing systems, is susceptible to a critical vulnerability identified as CVE-2022-38692. This vulnerability pertains to the missing size check for RSA keys during Certificate Type 0 validation, which can potentially cause memory buffer overflow. This issue is significant as it does not necessitate additional execution privileges, thereby increasing the ease and potential impact of exploitation. The vulnerability affects a broad range of users and systems, making it a prominent concern in the cybersecurity landscape.

Vulnerability Summary

CVE ID: CVE-2022-38692
Severity: Critical (CVSS Score: 9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

BootROM | All versions prior to the security patch

How the Exploit Works

The exploit hinges on the lack of size check for RSA keys during the validation of Certificate Type 0 in BootROM. In cryptographic operations, RSA keys are essential, and their management is a critical security concern. An attacker can craft a Certificate Type 0 with an oversized RSA key, which the BootROM would attempt to load into a buffer of a predefined size. The oversized key leads to a buffer overflow, potentially causing system instability or creating an opportunity for the execution of malicious code.

Conceptual Example Code

Below is a conceptual pseudocode example of how the vulnerability might be exploited:

def exploit(target):
# Prepare an oversized RSA key.
oversized_rsa_key = generate_rsa_key(size=OVERSIZED)
# Craft a Certificate Type 0 with the oversized RSA key.
crafted_certificate = craft_certificate(rsa_key=oversized_rsa_key)
# Send the crafted certificate to the target.
send_to_target(target, crafted_certificate)

This code generates an oversized RSA key, embeds it into a crafted Certificate Type 0, and sends it to the target. The BootROM on the target system will attempt to load this oversized key into a buffer, causing a buffer overflow.

Mitigation Guidance

To mitigate or resolve this vulnerability, users are strongly encouraged to apply the vendor’s security patch as soon as it becomes available. If the patch is not immediately accessible, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation. These systems can help detect and prevent attempts to exploit the vulnerability, thereby reducing the risk of a successful attack.