July 15, 2025 4 min to read

When Snyk Saved my Firebase Project

A Real world security Fix story

Yesterday, I got an unexpected visitor to my GitHub repository. Not a human contributor, but Snyk’s automated security bot, flagging a critical vulnerability in my Firebase project. What started as a routine dependency check turned into a fascinating case study of how modern security tools can catch threats that even experienced developers might miss.

The culprit? An uncontrolled resource consumption vulnerability lurking in the @grpc/grpc-js library, buried deep within Firebase’s dependency chain. With a severity score of 559 and the identifier SNYK-JS-GRPCGRPCJS-7242922, this wasn’t just another minor security hiccup—it was a legitimate denial of service risk sitting in production code.

The Technical Breakdown

What Actually Happened

The vulnerability existed in versions of @grpc/grpc-js prior to 1.8.22, 1.9.15, and 1.10.9. The problem centered around how the library handled the grpc.max_receive_message_length channel option. Instead of properly enforcing message size limits, the library would buffer or decompress incoming messages into memory regardless of their actual size.

Here’s the scary part: an attacker could craft messages that appeared to respect the configured limits but would consume massive amounts of memory during processing. Think of it like a zip bomb, but for gRPC messages. The server would dutifully allocate memory for what seemed like legitimate requests, only to find itself choking on unexpectedly large payloads.

The Attack Vector

The vulnerability manifested through a classic resource exhaustion pattern:

1. Initial Request: Attacker sends a gRPC message that passes basic size validation
2. Decompression Phase: The library begins processing the message, allocating memory for decompression
3. Memory Explosion: The decompressed content far exceeds expected limits
4. System Exhaustion: Server runs out of memory, leading to crashes or severe performance degradation

For a Firebase application, this could mean:

• Real-time database connections dropping
• Cloud Functions timing out
• Authentication services becoming unresponsive
• Complete application downtime

Snyk’s Intervention: Automated Security in Action

The Discovery Process

What impressed me most was how Snyk detected this vulnerability. It wasn’t just scanning my direct dependencies—it was analyzing the entire dependency tree. My package.json showed Firebase 9.22.1, but Snyk dug deeper, tracing through Firebase’s own dependencies to find the vulnerable @grpc/grpc-js library nested several layers down. The timeline was remarkable:

Detection: Snyk identified the vulnerability within hours of the security advisory Analysis: The platform assessed the impact on my specific project Solution: An automated pull request was generated with the fix Documentation: Complete vulnerability details and remediation steps were provided

The Automated Fix

Snyk’s solution was elegantly simple: upgrade Firebase from 9.22.1 to 10.1.0. This newer version included an updated @grpc/grpc-js dependency that had the vulnerability patched. The pull request modified two files:

package.json: Updated the Firebase version requirement package-lock.json: Locked in the secure dependency versions

What made this particularly valuable was the context Snyk provided. The bot didn’t just say “upgrade this”—it explained exactly why the upgrade was necessary, which vulnerability it addressed, and what the security implications were.

Technical Deep Dive: Understanding Resource Consumption Attacks

The Anatomy of the Attack

Resource consumption attacks exploit the fundamental tension between performance and security. Applications need to process data efficiently, but they also need to protect themselves from malicious inputs. The @grpc/grpc-js vulnerability occurred because the library optimized for performance without adequately considering security implications.

The specific attack pattern involved:

// Vulnerable code pattern (simplified)
function processMessage(compressedData) {
    // Check appears to validate size
    if (compressedData.length > MAX_MESSAGE_SIZE) {
        throw new Error('Message too large');
    }
    
    // But decompression can expand data significantly
    const decompressedData = decompress(compressedData);
    
    // This allocation might be much larger than expected
    const buffer = Buffer.alloc(decompressedData.length);
    // ... process data
}

The fix involved implementing proper resource limits throughout the entire message processing pipeline, not just at the initial validation stage.

Detection Challenges

These vulnerabilities are particularly insidious because they’re hard to detect through normal testing:

• Load testing might miss edge cases involving specific message types
• Unit tests typically don’t cover resource exhaustion scenarios
• Integration tests often run in resource-constrained environments that don’t reflect production conditions
• Security scans might focus on traditional vulnerabilities like injection attacks

This is where tools like Snyk become invaluable—they maintain databases of known vulnerabilities and can identify risks that traditional testing might miss.

Snyk Integration with Development Workflows

The seamless integration with GitHub workflows was particularly impressive. Snyk didn’t just identify the vulnerability—it created a pull request that fit naturally into my existing development process. The PR included:

• Clear vulnerability descriptions
• Impact assessments
• Remediation instructions
• Links to additional resources

This is my personal security experience with Snyk SAST with my live blog, In the end I would like to conclude as a good security isn’t about preventing all vulnerabilities—it’s about detecting and responding to them quickly when they do appear. Tools like Snyk make that rapid response possible, turning potential disasters into manageable maintenance tasks.