National Vulnerability Database

National Vulnerability Database

National Vulnerability
Database

CVE-2017-1000405 Detail

Current Description

The Linux Kernel versions 2.6.38 through 4.14 have a problematic use of pmd_mkdirty() in the touch_pmd() function inside the THP implementation. touch_pmd() can be reached by get_user_pages(). In such case, the pmd will become dirty. This scenario breaks the new can_follow_write_pmd()'s logic - pmd can become dirty without going through a COW cycle. This bug is not as severe as the original "Dirty cow" because an ext4 file (or any other regular file) cannot be mapped using THP. Nevertheless, it does allow us to overwrite read-only huge pages. For example, the zero huge page and sealed shmem files can be overwritten (since their mapping can be populated using THP). Note that after the first write page-fault to the zero page, it will be replaced with a new fresh (and zeroed) thp.

Source:  MITRE
Description Last Modified:  11/30/2017
View Analysis Description

Impact

CVSS v3.0 Severity and Metrics:

Base Score: 7.0 HIGH
Vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (V3 legend)
Impact Score: 5.9
Exploitability Score: 1.0


Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): High

CVSS v2.0 Severity and Metrics:

Base Score: 6.9 MEDIUM
Vector: (AV:L/AC:M/Au:N/C:C/I:C/A:C) (V2 legend)
Impact Subscore: 10.0
Exploitability Subscore: 3.4


Access Vector (AV): Local
Access Complexity (AC): Medium
Authentication (AU): None
Confidentiality (C): Complete
Integrity (I): Complete
Availability (A): Complete
Additional Information:
Allows unauthorized disclosure of information
Allows unauthorized modification
Allows disruption of service

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://www.securityfocus.com/bid/102032 Third Party Advisory VDB Entry
http://www.securitytracker.com/id/1040020
https://access.redhat.com/errata/RHSA-2018:0180
https://medium.com/bindecy/huge-dirty-cow-cve-2017-1000405-110eca132de0 Exploit Issue Tracking Third Party Advisory
https://source.android.com/security/bulletin/pixel/2018-02-01
https://www.exploit-db.com/exploits/43199/ Exploit Issue Tracking Third Party Advisory VDB Entry

Technical Details

Vulnerability Type (View All)

Change History

6 change records found - show changes

Quick Info

CVE Dictionary Entry:
CVE-2017-1000405
NVD Published Date:
11/30/2017
NVD Last Modified:
02/12/2018