CVE-2024-21484
📋 TL;DR
This vulnerability allows attackers to decrypt RSA-encrypted data by exploiting timing discrepancies in the jsrsasign library's PKCS1.5 and RSAOAEP decryption implementations. Systems using jsrsasign versions before 11.0.0 for RSA decryption operations are affected, particularly those where attackers can observe many ciphertexts encrypted with the same key.
💻 Affected Systems
- jsrsasign library
📦 What is this software?
Jsrsasign by Jsrsasign Project
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of encrypted data confidentiality, allowing attackers to decrypt sensitive information protected by RSA encryption.
Likely Case
Targeted decryption of specific encrypted messages or data after observing sufficient ciphertexts, potentially exposing sensitive information.
If Mitigated
Limited impact with proper key rotation, rate limiting, and monitoring for unusual decryption patterns.
🎯 Exploit Status
Exploitation requires collecting many ciphertexts encrypted with same key and performing timing analysis (Marvin attack).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 11.0.0
Vendor Advisory: https://github.com/kjur/jsrsasign/releases/tag/11.0.0
Restart Required: No
Instructions:
1. Update jsrsasign dependency to version 11.0.0 or later. 2. Update package.json to specify 'jsrsasign': '^11.0.0'. 3. Run npm update or equivalent package manager command. 4. Test RSA decryption functionality.
🔧 Temporary Workarounds
Replace RSA decryption with alternative library
allReplace jsrsasign RSA PKCS1.5 and RSAOAEP decryption calls with equivalent functions from a different cryptographic library that is not vulnerable.
🧯 If You Can't Patch
- Implement strict rate limiting on decryption operations to prevent collection of sufficient ciphertexts for timing analysis
- Rotate RSA keys frequently to limit window for ciphertext collection and analysis
🔍 How to Verify
Check if Vulnerable:
Check package.json or package-lock.json for jsrsasign version. If version is below 11.0.0 and RSA decryption is used, system is vulnerable.Check Version:
npm list jsrsasign or check package.json for versionVerify Fix Applied:
Verify jsrsasign version is 11.0.0 or higher in package.json and confirm RSA decryption functions work correctly after update.📡 Detection & Monitoring
Log Indicators:
- Unusually high volume of RSA decryption requests
- Multiple failed decryption attempts with timing patterns
Network Indicators:
- High volume of encrypted traffic to decryption endpoints
- Repeated similar-sized encrypted payloads
SIEM Query:
source=application_logs 'RSA.*decrypt' | stats count by src_ip, user | where count > threshold🔗 References
- https://github.com/kjur/jsrsasign/issues/598
- https://github.com/kjur/jsrsasign/releases/tag/11.0.0
- https://people.redhat.com/~hkario/marvin/
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-6070734
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBKJUR-6070733
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-6070732
- https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-6070731
- https://github.com/kjur/jsrsasign/issues/598
- https://github.com/kjur/jsrsasign/releases/tag/11.0.0
- https://people.redhat.com/~hkario/marvin/
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-6070734
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBKJUR-6070733
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-6070732
- https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-6070731
