The remote CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2021:3801 advisory.

  - An issue was discovered in Linux: KVM through Improper handling of VM_IO|VM_PFNMAP vmas in KVM can bypass     RO checks and can lead to pages being freed while still accessible by the VMM and guest. This allows users     with the ability to start and control a VM to read/write random pages of memory and can result in local     privilege escalation. (CVE-2021-22543)

  - A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when     processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested     guest (L2). Due to improper validation of the int_ctl field, this issue could allow a malicious L1 to     enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest     would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak     of sensitive data or potential guest-to-host escape. This flaw affects Linux kernel versions prior to     5.14-rc7. (CVE-2021-3653)

  - A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when     processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested     guest (L2). Due to improper validation of the virt_ext field, this issue could allow a malicious L1 to     disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the     L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire     system, leak of sensitive data or potential guest-to-host escape. (CVE-2021-3656)

  - arch/powerpc/kvm/book3s_rtas.c in the Linux kernel through 5.13.5 on the powerpc platform allows KVM guest     OS users to cause host OS memory corruption via rtas_args.nargs, aka CID-f62f3c20647e. (CVE-2021-37576)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

CentOS 7 : kernel (RHSA-2021:3801)

high Nessus Plugin ID 155547

Version 1.5