CVE-2018-1000199
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Last Modified:
Description
An address corruption flaw was discovered in the Linux kernel built with hardware breakpoint (CONFIG_HAVE_HW_BREAKPOINT) support. While modifying a h/w breakpoint via 'modify_user_hw_breakpoint' routine, an unprivileged user/process could use this flaw to crash the system kernel resulting in DoS OR to potentially escalate privileges on a the system.
Statement
This issue does not affect the versions of Linux kernel as shipped with Red Hat Enterprise Linux 5 and Red Hat Enterprise Linux 6.
This issue affects the version of the kernel package as shipped with Red Hat Enterprise Linux 7 and Red Hat Enterprise MRG 2. Future kernel updates for Red Hat Enterprise Linux 7 and Red Hat Enterprise MRG 2 may address this issue.
Mitigation
To mitigate this issue:
1) Save the following script in a 'CVE-2018-1000199.stp' file.
---
probe kernel.function("ptrace_set_debugreg") {
if ($n < 4)
$n = 4; /* set invalid debug register #, returns -EIO */
}
probe begin {
printk(0, "CVE-2018-1000199 mitigation loaded")
}
probe end {
printk(0, "CVE-2018-1000199 mitigation unloaded")
}
---
2) Install systemtap package and its dependencies
# yum install -y systemtap systemtap-runtime
# yum install -y kernel-devel kernel-debuginfo kernel-debuginfo-common
3) Build the mitigation kernel module as root.
# stap -r `uname -r` -m cve_2018_1000199.ko -g CVE-2018-1000199.stp -p4
4) Load the mitigation module as root
# staprun -L cve_2018_1000199.ko
Additional information
- Bugzilla 1568477: kernel: ptrace() incorrect error handling leads to corruption and DoS
- CWE-460: Improper Cleanup on Thrown Exception
- FAQ: Frequently asked questions about CVE-2018-1000199
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 7.8 | 5.5 |
Attack Vector | Local | Local |
Attack Complexity | High | Low |
Privileges Required | Low | Low |
User Interaction | None | None |
Scope | Changed | Unchanged |
Confidentiality Impact | High | None |
Integrity Impact | High | None |
Availability Impact | High | High |
CVSS v3 Vector
Red Hat: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Acknowledgements
Red Hat would like to thank Andy Lutomirski for reporting this issue.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
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