CVE-2023-42781
Cache-timing Attack vulnerability in apache-airflow (PyPI)
What is CVE-2023-42781 About?
Vault's implementation of Shamir's secret sharing was vulnerable to cache-timing attacks, allowing an attacker to reduce the search space for brute-forcing Shamir shares. This vulnerability affects Vault 1.13.1, 1.12.5, and 1.11.9. Exploitation is difficult, requiring specific conditions and observation capabilities.
Affected Software
Technical Details
The vulnerability lies in HashiCorp Vault's implementation of Shamir's secret sharing algorithm. This particular implementation utilized precomputed table lookups, which, while potentially improving performance, introduced a side channel susceptible to cache-timing attacks. An attacker with the ability to observe a large number of unseal operations on the host system can analyze the timing differences in cache hits and misses during these operations. These timing variations, correlated with the precomputed table lookups, can reveal partial information about the Shamir shares. By collecting enough timing data, the attacker can significantly reduce the computational complexity of brute-forcing the remaining unknown portions of the shares, thereby compromising the security of the secret sharing scheme. The attack vector relies on an observable side channel rather than direct code exploitation.
What is the Impact of CVE-2023-42781?
Successful exploitation may allow attackers to significantly reduce the effort required to brute-force Shamir shares, potentially leading to unauthorized access to secrets protected by the secret sharing scheme.
What is the Exploitability of CVE-2023-42781?
Exploitation of this cache-timing vulnerability is complex and requires specific conditions. The attacker must have access to the host system running Vault and the ability to observe a significant number of unseal operations. No direct authentication is required for observing the side channel, but access to the underlying host or a shared execution environment is a prerequisite. Privilege requirements would typically involve at least local user access to the host system to monitor CPU cache behavior or execution timings. This is primarily a local vulnerability, or potentially a co-located virtual machine attack in a multi-tenant cloud environment. Special conditions include the need for a large number of unseal operations to be observed and precise timing measurements. The risk factors that increase exploitation likelihood include shared hosting environments, or situations where an attacker can achieve even low-level access to the Vault host and generate continuous unseal attempts.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2023-42781?
Available Upgrade Options
- apache-airflow
- <2.7.3 → Upgrade to 2.7.3
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Book a demoAdditional Resources
- https://osv.dev/vulnerability/PYSEC-2023-231
- https://github.com/apache/airflow/pull/34939
- https://lists.apache.org/thread/7dnl8nszdxqyns57f3dw0sloy5dfl9o1
- https://github.com/apache/airflow/pull/34939
- http://www.openwall.com/lists/oss-security/2023/11/12/2
- https://lists.apache.org/thread/7dnl8nszdxqyns57f3dw0sloy5dfl9o1
What are Similar Vulnerabilities to CVE-2023-42781?
Similar Vulnerabilities: CVE-2022-2639 , CVE-2019-10650 , CVE-2018-12126 , CVE-2017-15361 , CVE-2016-10255
