Critical Vulnerability in Heimdal: Remote Service Impersonation Risk
Summary
ALPINE-CVE-2017-11103: Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. Affects heimdal versions < 7.4.0-r0. Fixed in 7.4.0-r0. How to fix ↓
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Background
Heimdal is an open-source implementation of the Kerberos 5 network authentication protocol, designed to provide secure authentication for users and services in a networked environment. It is widely used in various applications and systems to ensure secure communication and identity verification. However, a significant vulnerability has been identified that allows remote attackers to impersonate services, undermining the integrity of the authentication process.
Vulnerability Detail
Heimdal before version 7.4 introduces a vulnerability that allows remote attackers to impersonate services through Orpheus' Lyre attacks. This occurs because the service-principal names are obtained in a manner that violates the Kerberos 5 protocol specification. Specifically, in the function _krb5_extract_ticket(), the KDC-REP service name should be derived from the encrypted data in 'enc_part' rather than the unencrypted data in 'ticket'. Utilizing the unencrypted version creates an opportunity for successful server impersonation and other malicious attacks. This vulnerability is critical, with a CVSS score of 8.1, indicating a high severity level.
How To Fix
Minimum fixed version
7.4.0-r0
This is the first release that contains the fix.
sudo apk add --upgrade heimdalTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, it is advisable to limit access to the affected services and implement strict network controls to minimize exposure to potential attackers until the package can be updated. Additionally, consider monitoring network traffic for unusual authentication attempts.
Conclusion
The Heimdal vulnerability presents a significant risk to network security, allowing for potential service impersonation by attackers. It is crucial for users to update to the patched version 7.4.0-r0 or later to mitigate this risk. Implementing workarounds and monitoring for suspicious activity can help protect systems until the update is applied.
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FAQ
The vulnerability allows remote attackers to impersonate services, potentially leading to unauthorized access and data breaches.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
If an immediate update is not possible, implement network restrictions and monitor for suspicious activity as a temporary measure.
The CVSS score for this vulnerability is 8.1, indicating a high severity level.
More information about Heimdal can be found on its official documentation and repositories, which provide insights into its features and usage.
References
Related vulnerabilities
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