ID |
CVE-2019-19580
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Summary |
An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations, because of an incomplete fix for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations. Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All security-supported versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Note that these attacks require very precise timing, which may be difficult to exploit in practice. |
References |
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Vulnerable Configurations |
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CVSS |
Base: | 6.0 (as of 03-01-2020 - 22:15) |
Impact: | |
Exploitability: | |
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CWE |
CWE-362 |
CAPEC |
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Leveraging Race Conditions
The adversary targets a race condition occurring when multiple processes access and manipulate the same resource concurrently, and the outcome of the execution depends on the particular order in which the access takes place. The adversary can leverage a race condition by "running the race", modifying the resource and modifying the normal execution flow. For instance, a race condition can occur while accessing a file: the adversary can trick the system by replacing the original file with his version and cause the system to read the malicious file.
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Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. A typical example is file access. The adversary can leverage a file access race condition by "running the race", meaning that they would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the adversary could replace or modify the file, causing the application to behave unexpectedly.
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Access |
Vector | Complexity | Authentication |
NETWORK |
MEDIUM |
SINGLE |
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Impact |
Confidentiality | Integrity | Availability |
PARTIAL |
PARTIAL |
PARTIAL |
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cvss-vector
via4
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AV:N/AC:M/Au:S/C:P/I:P/A:P
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refmap
via4
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Last major update |
03-01-2020 - 22:15 |
Published |
11-12-2019 - 18:16 |
Last modified |
03-01-2020 - 22:15 |