CVE-2017-7495
A vulnerability was found in the Linux kernel where filesystems mounted with data=ordered mode may allow an attacker to read stale data from recently allocated blocks in new files after a system 'reset' by abusing ext4 mechanics of delayed allocation.
Find out more about CVE-2017-7495 from the MITRE CVE dictionary dictionary and NIST NVD.
Statement
This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 5 and 6.
This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 and MRG-2. Future Linux kernel updates for the respective releases may address this issue.
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CVSS v3 metrics
| CVSS3 Base Score | 6.2 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity Impact | None |
| Availability Impact | None |
Red Hat Security Errata
| Platform | Errata | Release Date |
|---|---|---|
| Red Hat Enterprise Linux 7 (kernel) | RHSA-2017:1842 | 2017-08-01 |
| Red Hat MRG Grid for RHEL 6 Server v.2 (kernel-rt) | RHSA-2017:2669 | 2017-09-06 |
| Red Hat Enterprise Linux for Real Time for NFV (v. 7) (kernel-rt) | RHSA-2017:2077 | 2017-08-01 |
Affected Packages State
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise MRG 2 | realtime-kernel | Will not fix |
| Red Hat Enterprise Linux 7 | kernel-alt | Not affected |
| Red Hat Enterprise Linux 6 | kernel | Not affected |
| Red Hat Enterprise Linux 5 | kernel | Not affected |
Acknowledgements
Red Hat would like to thank Takeshi Nishimura (NEC) for reporting this issue.Mitigation
Alternative filesystems may be used in place of ext4 in case of sensitive data leak. Alternatively, don't hard reset the system.