NVD Vulnerability Detail

CVE-2017-5551

Summary	The simple_set_acl function in fs/posix_acl.c in the Linux kernel before 4.9.6 preserves the setgid bit during a setxattr call involving a tmpfs filesystem, which allows local users to gain group privileges by leveraging the existence of a setgid program with restrictions on execute permissions. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-7097.
Publication Date	Feb. 6, 2017, 3:59 p.m.
Registration Date	Jan. 26, 2021, 1:26 p.m.
Last Update	Nov. 21, 2024, 12:27 p.m.

Affected software configurations

Configuration1		or higher	or less	more than	less than
cpe:2.3:o:linux:linux_kernel::::::::			4.9.5

Related information, measures and tools

No	URL	タグ
1	http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31	Issue Tracking Patch Third Party Advisory
2	http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31	Issue Tracking Patch Third Party Advisory
3	http://www.debian.org/security/2017/dsa-3791
4	http://www.debian.org/security/2017/dsa-3791
5	http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.6	Release Notes Vendor Advisory
6	http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.6	Release Notes Vendor Advisory
7	http://www.openwall.com/lists/oss-security/2017/01/21/3	Mailing List Patch Third Party Advisory
8	http://www.openwall.com/lists/oss-security/2017/01/21/3	Mailing List Patch Third Party Advisory
9	http://www.securityfocus.com/bid/95717	Third Party Advisory VDB Entry
10	http://www.securityfocus.com/bid/95717	Third Party Advisory VDB Entry
11	http://www.securitytracker.com/id/1038053
12	http://www.securitytracker.com/id/1038053
13	https://bugzilla.redhat.com/show_bug.cgi?id=1416126	Issue Tracking Patch
14	https://bugzilla.redhat.com/show_bug.cgi?id=1416126	Issue Tracking Patch
15	https://github.com/torvalds/linux/commit/497de07d89c1410d76a15bec2bb41f24a2a89f31	Issue Tracking Patch Third Party Advisory
16	https://github.com/torvalds/linux/commit/497de07d89c1410d76a15bec2bb41f24a2a89f31	Issue Tracking Patch Third Party Advisory

Common Vulnerabilities List

JVN Vulnerability Information

Linux Kernel の fs/posix_acl.c の simple_set_acl 関数におけるグループ権限を取得される脆弱性

Title	Linux Kernel の fs/posix_acl.c の simple_set_acl 関数におけるグループ権限を取得される脆弱性
Summary	Linux Kernel の fs/posix_acl.c の simple_set_acl 関数は、tmpfs ファイルシステムを含む setxattr コールの際、setgid bit を保存するため、グループ権限を取得される脆弱性が存在します。本脆弱性は、CVE-2016-7097 に対する修正が不完全だったことに起因する問題です。
Possible impacts	ローカルユーザにより、パーミッション実行時に、制限を伴う setgid プログラムの存在を利用されることで、グループ権限を取得される可能性があります。
Solution	ベンダより正式な対策が公開されています。ベンダ情報を参照して適切な対策を実施してください。
Publication Date	Jan. 26, 2017, midnight
Registration Date	Feb. 23, 2017, 2:15 p.m.
Last Update	Feb. 23, 2017, 2:15 p.m.

Affected System

Linux

Linux Kernel 4.9.6 未満

CVE (情報セキュリティ共通脆弱性識別子)

No	Name	URL
Common Vulnerabilities and Exposures (CVE)
1	CVE-2017-5551	http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5551
National Vulnerability Database (NVD)
2	CVE-2017-5551	http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2017-5551

CWE (共通脆弱性タイプ一覧)

No	Name	URL
JVNDB
1	CWE-264	https://jvndb.jvn.jp/ja/cwe/CWE-264.html

ベンダー情報

No	Name	URL
ChangeLog
1	ChangeLog-4.9.6	https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.6
GitHub
2	tmpfs: clear S_ISGID when setting posix ACLs	https://github.com/torvalds/linux/commit/497de07d89c1410d76a15bec2bb41f24a2a89f31
Linux Kernel
3	Linux Kernel Archives	http://www.kernel.org
Linux kernel source tree
4	tmpfs: clear S_ISGID when setting posix ACLs	http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31
Red Hat Bugzilla
5	Bug 1416126	https://bugzilla.redhat.com/show_bug.cgi?id=1416126

Change Log

No	Changed Details	Date of change
0	[2017年02月23日] 掲載	Feb. 17, 2018, 10:37 a.m.