CVE-2019-12817
📋 TL;DR
A memory management vulnerability in the Linux kernel for PowerPC systems allows unrelated processes to read/write each other's virtual memory when using mmap above 512 TB. Only PowerPC systems running affected Linux kernel versions are impacted, potentially leading to privilege escalation or data exposure.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Fedora by Fedoraproject
Fedora by Fedoraproject
Leap by Opensuse
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Full privilege escalation from unprivileged user to root, complete system compromise, or sensitive data exposure between processes.
Likely Case
Information disclosure between processes, potential privilege escalation in multi-user environments, or container escape in virtualized environments.
If Mitigated
Limited impact due to PowerPC architecture rarity and specific mmap usage requirements, with proper access controls reducing exposure.
🎯 Exploit Status
Exploitation requires local access and knowledge of mmap usage patterns. No publicly available exploit code identified in references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 5.1.15 or later
Vendor Advisory: https://access.redhat.com/errata/RHSA-2019:2703
Restart Required: Yes
Instructions:
1. Update Linux kernel to version 5.1.15 or later. 2. For distributions: Use package manager (yum update kernel, apt-get upgrade linux-image). 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Restrict mmap usage
linuxLimit processes from using mmap above 512 TB address space via ulimit or security modules
ulimit -v [LIMIT]
echo 0 > /proc/sys/vm/overcommit_memory
🧯 If You Can't Patch
- Isolate PowerPC systems from untrusted users and restrict local access
- Implement strict process isolation and monitor for unusual memory access patterns
🔍 How to Verify
Check if Vulnerable:
Check kernel version and architecture: uname -r and uname -m. If PowerPC (ppc64le) and kernel < 5.1.15, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is 5.1.15 or later: uname -r should show 5.1.15+📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages related to mmu_context_book3s64.c
- Unexpected process memory access patterns in audit logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("mmu_context_book3s64" OR "CVE-2019-12817")🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00025.html
- http://www.openwall.com/lists/oss-security/2019/06/24/5
- http://www.securityfocus.com/bid/108884
- https://access.redhat.com/errata/RHSA-2019:2703
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.1.15
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ca72d88378b2f2444d3ec145dd442d449d3fefbc
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OTLN3KQYEEWWAJYA4BUYYDMWWXCJQNV2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSKLL2374YGFQR6LSVCFGTTCRGBTLAWZ/
- https://seclists.org/bugtraq/2019/Aug/13
- https://support.f5.com/csp/article/K12876166
- https://support.f5.com/csp/article/K12876166?utm_source=f5support&%3Butm_medium=RSS
- https://usn.ubuntu.com/4031-1/
- https://www.debian.org/security/2019/dsa-4495
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00025.html
- http://www.openwall.com/lists/oss-security/2019/06/24/5
- http://www.securityfocus.com/bid/108884
- https://access.redhat.com/errata/RHSA-2019:2703
- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.1.15
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ca72d88378b2f2444d3ec145dd442d449d3fefbc
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OTLN3KQYEEWWAJYA4BUYYDMWWXCJQNV2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WSKLL2374YGFQR6LSVCFGTTCRGBTLAWZ/
- https://seclists.org/bugtraq/2019/Aug/13
- https://support.f5.com/csp/article/K12876166
- https://support.f5.com/csp/article/K12876166?utm_source=f5support&%3Butm_medium=RSS
- https://usn.ubuntu.com/4031-1/
- https://www.debian.org/security/2019/dsa-4495
