CVE-2024-38807: Spring Boot Loader Auth Bypass Vulnerability

CVE-2024-38807 Overview

CVE-2024-38807 is a signature forgery vulnerability affecting applications that use spring-boot-loader or spring-boot-loader-classic components. This vulnerability specifically impacts applications containing custom code that performs signature verification of nested JAR files. The flaw allows content that appears to have been signed by one signer to have actually been signed by another party, undermining the integrity of cryptographic signature verification.

Critical Impact

Applications relying on signature verification for nested JAR files may accept maliciously signed content as legitimate, potentially allowing unauthorized code execution or the introduction of tampered dependencies.

Affected Products

• Spring Boot applications using spring-boot-loader
• Spring Boot applications using spring-boot-loader-classic
• Applications with custom signature verification for nested JAR files

Discovery Timeline

• 2024-08-23 - CVE-2024-38807 published to NVD
• 2025-03-27 - Last updated in NVD database

Technical Details for CVE-2024-38807

Vulnerability Analysis

This vulnerability falls under CWE-290 (Authentication Bypass by Spoofing), which occurs when an attacker can impersonate a trusted entity by exploiting weaknesses in authentication mechanisms. In the context of CVE-2024-38807, the Spring Boot loader components fail to properly validate cryptographic signatures on nested JAR files, enabling signature forgery attacks.

The vulnerability requires local access to exploit and involves high attack complexity. An attacker with low privileges could potentially compromise the confidentiality and integrity of affected applications without requiring user interaction. The attack vector is local, meaning an attacker would need some level of access to the system running the vulnerable application.

Root Cause

The root cause stems from improper validation logic in the signature verification process for nested JAR files within Spring Boot loader components. When applications implement custom signature verification code using these loaders, the verification may incorrectly attribute signatures, allowing content signed by one party to appear as if signed by a different, potentially trusted signer.

Attack Vector

The attack requires local access to the target system. An attacker could craft a malicious nested JAR file with forged signature attributes. When the vulnerable application attempts to verify the signature of the nested JAR, the flawed verification logic may accept the malicious content as legitimately signed by a trusted party. This could enable supply chain attacks where tampered dependencies are introduced into applications that rely on signature verification for security.

The exploitation scenario involves:

1. An attacker gaining local access to a system running a vulnerable Spring Boot application
2. Replacing or injecting a maliciously crafted nested JAR file
3. The application's custom signature verification accepting the forged signature
4. The tampered code executing with the privileges of the application

Detection Methods for CVE-2024-38807

Indicators of Compromise

• Unexpected modifications to nested JAR files within Spring Boot applications
• Signature verification logs showing mismatched or unusual signer information
• Unexplained changes to application behavior after JAR file modifications
• Audit trail anomalies in JAR file signature metadata

Detection Strategies

• Monitor file integrity of Spring Boot application JAR files and their nested dependencies
• Implement logging for all signature verification operations to detect anomalous signer identities
• Review application code for custom signature verification implementations using spring-boot-loader or spring-boot-loader-classic
• Deploy SentinelOne Singularity Platform to detect suspicious file modifications and unauthorized code execution attempts

Monitoring Recommendations

• Enable verbose logging for signature verification processes in Spring Boot applications
• Set up alerts for failed or suspicious signature verification attempts
• Monitor for unauthorized file system access to application deployment directories
• Track process execution originating from nested JAR files for anomalous behavior

How to Mitigate CVE-2024-38807

Immediate Actions Required

• Inventory all applications using spring-boot-loader or spring-boot-loader-classic components
• Review custom signature verification code for nested JAR files
• Update affected Spring Boot components to patched versions as recommended by VMware
• Implement additional validation layers for signature verification until patches are applied

Patch Information

VMware has addressed this vulnerability in updated versions of Spring Boot. Refer to the Spring Security Advisory for specific version information and upgrade guidance. NetApp has also published guidance in their Security Advisory NTAP-20250117-0006.

Organizations should prioritize upgrading to the latest patched versions of Spring Boot that address this signature verification flaw.

Workarounds

• Avoid relying solely on nested JAR signature verification for security-critical decisions
• Implement additional out-of-band signature verification mechanisms
• Restrict file system access to application deployment directories to prevent JAR file tampering
• Consider using container isolation or sandboxing to limit the impact of potential exploitation

# Verify Spring Boot version and dependencies
./mvnw dependency:tree | grep spring-boot-loader
# Or for Gradle projects
./gradlew dependencies | grep spring-boot-loader