CVE-2023-38545
CVE-2023-38545
Weakness (CWE)
CVSS Vector
v3.1- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Description
This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means "let the host resolve the name" could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with.
Comprehensive Technical Analysis of CVE-2023-38545
1. Vulnerability Assessment and Severity Evaluation
CVE ID: CVE-2023-38545
Description:
CVE-2023-38545 is a heap-based buffer overflow vulnerability in the SOCKS5 proxy handshake mechanism of curl. This flaw occurs when curl is instructed to pass the hostname to the SOCKS5 proxy for resolution. If the hostname exceeds 255 bytes, curl is supposed to switch to local name resolution and pass only the resolved address. However, due to this bug, the local variable indicating the resolution method can be incorrectly set during a slow SOCKS5 handshake, leading to the copying of an overly long hostname into the target buffer instead of the resolved address.
CVSS Score: 9.8
Severity: Critical
The high CVSS score of 9.8 indicates that this vulnerability is highly severe. It can lead to arbitrary code execution, denial of service, or information disclosure, making it a critical issue for systems using curl with SOCKS5 proxies.
2. Potential Attack Vectors and Exploitation Methods
Attack Vectors:
- Network-Based Attacks: An attacker can exploit this vulnerability by crafting a malicious URL with an overly long hostname and enticing a user to access it via
curlthrough a SOCKS5 proxy. - Man-in-the-Middle (MitM) Attacks: An attacker intercepting network traffic could manipulate the SOCKS5 handshake to exploit this vulnerability.
Exploitation Methods:
- Buffer Overflow: By sending a hostname longer than 255 bytes, an attacker can cause a buffer overflow in the heap, potentially leading to arbitrary code execution or a denial of service.
- Memory Corruption: The overflow can corrupt adjacent memory, leading to unpredictable behavior or crashes.
3. Affected Systems and Software Versions
Affected Software:
curlversions prior to the patch release addressing CVE-2023-38545.
Affected Systems:
- Any system or application that uses
curlwith SOCKS5 proxies, including but not limited to:- Web servers and applications
- Network management tools
- Automated scripts and utilities
- IoT devices and embedded systems
4. Recommended Mitigation Strategies
Immediate Actions:
- Update
curl: Ensure that all systems are updated to the latest version ofcurlthat includes the patch for CVE-2023-38545. - Disable SOCKS5 Proxy: If updating is not immediately possible, consider disabling the use of SOCKS5 proxies until the patch can be applied.
- Network Monitoring: Implement network monitoring to detect and block suspicious traffic patterns that may indicate an attempt to exploit this vulnerability.
Long-Term Strategies:
- Regular Patch Management: Establish a robust patch management process to ensure timely updates of all software components.
- Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate similar issues.
- Input Validation: Enhance input validation mechanisms to prevent overly long hostnames from being processed.
5. Impact on Cybersecurity Landscape
Broader Implications:
- Widespread Use of
curl: Given the widespread use ofcurlin various applications and systems, this vulnerability poses a significant risk across multiple sectors. - Supply Chain Risks: Organizations relying on third-party services or software that use
curlare also at risk, highlighting the importance of supply chain security. - Increased Attack Surface: The vulnerability increases the attack surface for systems using SOCKS5 proxies, making them more susceptible to network-based attacks.
6. Technical Details for Security Professionals
Technical Analysis:
- Heap Buffer Overflow: The vulnerability is a classic heap buffer overflow, where the hostname exceeding 255 bytes is copied into a buffer without proper bounds checking.
- SOCKS5 Handshake: The flaw occurs during the SOCKS5 handshake process, where the decision to resolve the hostname locally or via the proxy is made.
- Code Review: Security professionals should review the SOCKS5 handshake code in
curlto understand the flaw and ensure similar issues are not present in other parts of the codebase.
Detection and Response:
- Intrusion Detection Systems (IDS): Configure IDS to detect anomalous SOCKS5 handshake traffic, particularly long hostnames.
- Log Analysis: Analyze logs for any unusual patterns or errors related to SOCKS5 proxy usage.
- Incident Response: Develop an incident response plan specifically for buffer overflow vulnerabilities, including steps for containment, eradication, and recovery.
Conclusion: CVE-2023-38545 is a critical vulnerability that requires immediate attention from cybersecurity professionals. By understanding the technical details and implementing the recommended mitigation strategies, organizations can significantly reduce the risk posed by this flaw. Regular updates, robust security practices, and proactive monitoring are essential to maintaining a secure cybersecurity posture.