CVE-2024-31497 is a medium-severity vulnerability that affects multiple applications, including PuTTY, FileZilla Client, and WinSCP. This vulnerability allows attackers to recover a user's NIST P-521 secret key through biased ECDSA nonce generation, which can be exploited via a network attack. The CVSS score is 5.9, indicating a moderate risk level, but organizations should not underestimate the potential consequences.
The importance of addressing this vulnerability stems from the potential for serious real-world risks. If an attacker successfully exploits this vulnerability, they may gain unauthorized access to systems and data that rely on compromised private keys. This could lead to supply-chain attacks or unauthorized access to other services, especially if the same private key is used across multiple systems.
Currently, there is a known exploit for this vulnerability, which adds to the urgency for organizations to prioritize remediation. Although it is not categorized as a high-profile vulnerability, the implications of a successful attack are significant, particularly in environments relying on SSH for secure communications.
Organizations should prioritize patching immediately, as the vulnerability affects versions of PuTTY from 0.68 to 0.80 before 0.81, as well as other applications like FileZilla and WinSCP. Prompt action will help mitigate the risks associated with this vulnerability.
Vulnerability Details
This vulnerability allows attackers to recover a user's NIST P-521 secret key by exploiting biased ECDSA nonce generation in PuTTY versions 0.68 through 0.80. The attack can be executed quickly, requiring only approximately 60 signatures. This situation becomes particularly critical when an adversary can read messages signed by PuTTY or Pageant, especially in public Git services where signed messages are stored.
The CVSS score of 5.9 indicates a medium severity level with a high attack complexity. The confidentiality impact is high, while integrity and availability impacts are none. This vulnerability is categorized under CWE-338.
The affected products include PuTTY, FileZilla Client, WinSCP, TortoiseGit, TortoiseSVN, and Fedora. The vulnerability was publicly disclosed on April 15, 2024.
Technical Analysis
The root cause of this vulnerability lies in the biased nonce generation for ECDSA signatures in the affected versions of PuTTY. Attackers can exploit this flaw remotely without needing to authenticate. The attack complexity is high, requiring a specific set of conditions to be met, including the ability to read signed messages.
In terms of attack vector, this vulnerability is classified as a network attack. No user interaction is necessary, and no privileges are required to exploit it. The impact on confidentiality is significant, as compromised keys can lead to unauthorized access to systems and data.
Risk & Impact Analysis
Risk to organizations includes the potential for unauthorized access to sensitive data and systems. If an attacker recovers a private key through this vulnerability, they could perform supply-chain attacks on software maintained in Git. Organizations using the affected software should evaluate their exposure and the potential blast radius of an attack.
Given the medium severity of this vulnerability, organizations should address it in their priority patch cycle to reduce the risk of exploitation. The presence of a known exploit heightens the urgency for remediation.
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following products are affected by CVE-2024-31497: - PuTTY: Versions 0.68 through 0.80 (prior to 0.81) - FileZilla Client: Versions prior to 3.67.0 - WinSCP: Versions prior to 6.3.3 - TortoiseGit: Versions prior to 2.15.0.1 - TortoiseSVN: Versions through 1.14.6 - Fedora: Versions 38, 39, and 40. Organizations should consider all versions prior to vendor patches as vulnerable.
Mitigation & Remediation
To mitigate the risks associated with CVE-2024-31497, organizations should implement the following measures: 1. **Patch the affected applications** to the latest versions that address this vulnerability. 2. **Review SSH key usage** across systems and rotate keys for any potentially affected services. 3. **Monitor network traffic** for any unauthorized access attempts, especially from untrusted sources. 4. Organizations should consider implementing penetration testing to validate their security posture and identify any other vulnerabilities.
Detection Guidance
Organizations should monitor for the following indicators of compromise related to this vulnerability: - Anomalous SSH connection attempts, especially from untrusted networks. - Unexpected logins or access to systems using compromised keys. - Unusual patterns in signing activity that could indicate exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2024-31497 highlights the importance of secure cryptographic practices and key management. This vulnerability represents a trend where poorly implemented cryptographic functions can lead to severe security risks. Security teams should learn from this incident to enhance their cryptographic practices and ensure rigorous testing of key management solutions.
Organizations should also consider investing in regular security assessments and adopting best practices for cryptographic operations. By doing so, they can build robust defenses against similar vulnerabilities in the future. Furthermore, teams should review their incident response plans to ensure they are prepared for potential key compromises.
For additional resources, organizations can refer to the following articles: penetration testing methodology, vulnerability management program design, and API penetration testing guide for further insights into maintaining security.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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