CVE-2015-3006 in QFX3500
Summary
by MITRE
On the QFX3500 and QFX3600 platforms, the number of bytes collected from the RANDOM_INTERRUPT entropy source when the device boots up is insufficient, possibly leading to weak or duplicate SSH keys or self-signed SSL/TLS certificates. Entropy increases after the system has been up and running for some time, but immediately after boot, the entropy is very low. This issue only affects the QFX3500 and QFX3600 switches. No other Juniper Networks products or platforms are affected by this weak entropy vulnerability.
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Analysis
by VulDB Data Team • 05/03/2022
The vulnerability described in CVE-2015-3006 represents a critical cryptographic weakness affecting Juniper Networks QFX3500 and QFX3600 switching platforms. This issue stems from insufficient entropy collection during the initial boot process, specifically when the device gathers random data from the RANDOM_INTERRUPT entropy source. The fundamental problem lies in the inadequate randomness quality during system initialization, which directly impacts the cryptographic key generation process. According to CWE-330, this represents a weakness in entropy sources where insufficient randomness leads to predictable cryptographic outputs. The vulnerability affects the generation of SSH keys and self-signed SSL/TLS certificates, creating potential security risks that could be exploited by attackers with sufficient computational resources to perform cryptographic attacks against weak keys.
The technical flaw manifests as a temporal entropy deficiency that occurs immediately upon system boot, where the random number generator fails to collect sufficient unpredictable data from the interrupt-based entropy source. This weakness persists until the system has been operational for an extended period, allowing the entropy pool to gradually accumulate sufficient randomness through normal system operations. The low entropy state during boot creates deterministic cryptographic outputs that can be potentially guessed or brute-forced by adversaries. This vulnerability directly impacts the security posture of affected devices by potentially generating cryptographically weak keys that do not meet industry standards for cryptographic strength. The issue is classified under the MITRE ATT&CK technique T1552.001 for Unsecured Credentials, as it enables potential credential compromise through weak cryptographic key generation.
The operational impact of this vulnerability extends beyond simple key generation weaknesses to potentially compromise the entire security infrastructure of affected networks. When SSH keys or SSL/TLS certificates are generated with insufficient entropy, they become vulnerable to various attack vectors including key recovery attacks, man-in-the-middle scenarios, and unauthorized access to network devices. The weakness is particularly concerning because it affects the initial system boot state, which is often when security-critical services are first initialized and when network access is most critical. Organizations running QFX3500 and QFX3600 switches face potential exposure to attackers who could exploit these weak keys to gain unauthorized access to network infrastructure, particularly during maintenance windows or system reboots when the entropy deficiency is most pronounced. The vulnerability affects only these specific platform models, indicating a targeted issue with their entropy collection mechanisms rather than a broader product line problem.
Mitigation strategies for this vulnerability require immediate attention and systematic approach to address the entropy deficiency during system boot. The recommended solution involves applying the appropriate Juniper Networks security patches and firmware updates that address the entropy collection mechanism during device initialization. Network administrators should implement procedures to ensure that affected devices are updated promptly and that system reboots are scheduled during maintenance windows to minimize exposure. The entropy collection process should be monitored and validated to ensure adequate randomness is generated before cryptographic keys are created. Organizations should also consider implementing additional security measures such as manual key generation with verified entropy sources, regular key rotation policies, and monitoring for suspicious authentication attempts that might indicate exploitation attempts. The mitigation process aligns with industry best practices for entropy management and cryptographic key generation as outlined in NIST SP 800-90A and other cryptographic standards, ensuring that the entropy sources meet minimum requirements for cryptographic security.