A vulnerability in the cirrus_bitblt_cputovideo bitblit copy routine in Xen could allow a local attacker to gain elevated privileges.
The vulnerability is due to improper memory operations performed by the affected software. An attacker with administrative privileges on a guest operating system could exploit this vulnerability by copying crafted input to the targeted system. An exploit could trigger an out of bounds memory write that the attacker could leverage to gain elevated privileges on the host operating system.
Xen.org has confirmed the vulnerability and released software updates.
The vulnerability is due to insufficient memory checks by the cirrus_bitblt_cputovideo bitblit copy routine while the affected software is running in CIRRUS_BLTMODE_MEMSYSSRC mode.
As a result, an attacker with administrative privileges on a guest system could trigger an out of bounds write condition that could be leveraged to gain elevated privileges on the host system.
To exploit this vulnerability, an attacker must have administrative privileges on the targeted guest operating system. This access requirement may reduce the likelihood of a successful exploit.
ARM systems and systems using only PV guests are not vulnerable.
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to access local systems.
Administrators are advised to allow only privileged users to access administration or management systems.
Administrators are advised to monitor affected systems.
Xen.org has released a security advisory at the following link: XSA-209
Red Hat has released updated software for registered subscribers at the following link: Red Hat Network. Red Hat packages can be updated on Red Hat Enterprise Linux versions 5 and later by using the yum tool.
QEMU has released software patches at the following link: QEMU patches
QEMU has released an additional security advisory and updated packages to address the Xen qemu Cirrus video emulation memory corruption vulnerability.
6.0 for RHEL 7 (x86_64) | 7.0 (x86_64) | 8.0 for RHEL 7 (x86_64) | 9.0 (x86_64) | 10.0 for RHEL 7 (x86_64)
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