CVE-2025-55398

Comprehensive Technical Analysis of CVE-2025-55398

1. Vulnerability Assessment and Severity Evaluation

CVE ID: CVE-2025-55398 CVSS Score: 9.8

The vulnerability in question affects the mouse07410 asn1c library, specifically versions up to and including 0.9.29. The issue lies within the UPER (Unaligned Packed Encoding Rules) decoders, which fail to enforce INTEGER constraints when the bound is positive and exceeds 32 bits in length. This failure can lead to the processing of incorrect or malicious input, potentially causing unpredictable behavior, crashes, or even arbitrary code execution.

Given the CVSS score of 9.8, this vulnerability is considered critical. The high score indicates a significant risk to systems using the affected library, emphasizing the need for immediate attention and mitigation.

2. Potential Attack Vectors and Exploitation Methods

Attack Vectors:

• Malicious Input: An attacker could craft specially designed ASN.1 encoded data that exploits the lack of constraint enforcement. This data could be sent to systems using the vulnerable decoder, leading to unintended behavior.
• Network Protocols: If the vulnerable library is used in network protocols that rely on ASN.1 encoding, an attacker could exploit this vulnerability over the network.
• File Parsing: Applications that parse ASN.1 encoded files using the affected library could be targeted by providing malicious files.

Exploitation Methods:

• Buffer Overflow: By providing an INTEGER value that exceeds the expected bounds, an attacker could trigger a buffer overflow, potentially leading to arbitrary code execution.
• Denial of Service (DoS): An attacker could send malformed data to cause the application to crash or become unresponsive, leading to a DoS condition.
• Data Corruption: Incorrect processing of ASN.1 data could lead to data corruption, affecting the integrity and reliability of the application.

3. Affected Systems and Software Versions

Affected Software:

• mouse07410 asn1c versions up to and including 0.9.29.

Affected Systems:

• Any system or application that uses the mouse07410 asn1c library for ASN.1 encoding/decoding.
• Network devices and protocols that rely on ASN.1 encoding.
• File parsers and data processing applications that handle ASN.1 encoded data.

4. Recommended Mitigation Strategies

Immediate Actions:

• Patching: Upgrade to a patched version of the mouse07410 asn1c library as soon as it becomes available.
• Input Validation: Implement additional input validation to ensure that INTEGER values do not exceed expected bounds.
• Network Filters: Use network filters to block or sanitize malicious ASN.1 encoded data.

Long-Term Strategies:

• Code Review: Conduct a thorough code review of the ASN.1 decoding logic to identify and fix similar issues.
• Security Testing: Incorporate security testing into the development lifecycle to catch such vulnerabilities early.
• Monitoring: Implement monitoring and logging to detect and respond to any suspicious activities related to ASN.1 data processing.

5. Impact on Cybersecurity Landscape

The discovery of this vulnerability highlights the importance of robust input validation and constraint enforcement in data encoding/decoding libraries. Given the widespread use of ASN.1 in various industries, including telecommunications and networking, the impact of such vulnerabilities can be far-reaching. Organizations must prioritize the security of their data processing libraries and ensure that they are regularly updated and patched.

6. Technical Details for Security Professionals

Vulnerability Details:

• The vulnerability is due to a failure in enforcing INTEGER constraints in the UPER decoders when the bound is positive and exceeds 32 bits.
• This can lead to the processing of incorrect or malicious input, potentially causing buffer overflows, crashes, or arbitrary code execution.

Detection and Response:

• Detection: Use intrusion detection systems (IDS) and intrusion prevention systems (IPS) to detect anomalous ASN.1 encoded data.
• Response: Implement incident response plans to quickly address any exploitation attempts. Ensure that affected systems are patched and that additional input validation is in place.

Code Example:

// Example of a vulnerable decoder function
int decode_integer(const uint8_t *data, size_t length, int *value) {
    // Vulnerable code that does not enforce constraints
    *value = decode_uper_integer(data, length);
    return 0;
}

// Example of a patched decoder function
int decode_integer(const uint8_t *data, size_t length, int *value) {
    // Enforce constraints
    if (length > 4) {
        return -1; // Error: length exceeds 32 bits
    }
    *value = decode_uper_integer(data, length);
    return 0;
}

Conclusion: CVE-2025-55398 is a critical vulnerability affecting the mouse07410 asn1c library. Organizations must take immediate action to mitigate the risk by upgrading to patched versions, implementing additional input validation, and enhancing their security posture to protect against similar vulnerabilities in the future.