An exploitable code execution vulnerability exists in the quota file functionality of E2fsprogs 1.45.3. A specially crafted ext4 partition can cause an out-of-bounds write on the heap, resulting in code execution. An attacker can corrupt a partition to trigger this vulnerability. Reference: https://seclists.org/bugtraq/2019/Sep/58 https://talosintelligence.com/vulnerability_reports/TALOS-2019-0887
Created e2fsprogs tracking bugs for this issue: Affects: fedora-all [bug 1768556]
This is fixed by: commit 8dbe7b475ec5e91ed767239f0e85880f416fc384 Author: Theodore Ts'o <tytso> Date: Sun Sep 1 00:59:16 2019 -0400 libsupport: add checks to prevent buffer overrun bugs in quota code A maliciously corrupted file systems can trigger buffer overruns in the quota code used by e2fsck. To fix this, add sanity checks to the quota header fields as well as to block number references in the quota tree. Addresses: CVE-2019-5094 Addresses: TALOS-2019-0887 Signed-off-by: Theodore Ts'o <tytso>
Analysis notes: This flaw is triggered by a malformed/specially-crafted ext2/3/4 partition. You need to run the e2fsck utility on the said partition in order to trigger the flaw. Since the e2fsck cannot only be run as a privileged user, the attacker will need to social engineer/convince the system administrator to run this utility on the corrupted partition. Also the corrupted partition will first need to exists on the system either via a locally attached hard drive or a network device. Based on the above, it seems like exploiting this flaw will need some previous privileged access on the system by the attacker.
Upstream commit: https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/commit/?id=8dbe7b475ec5e91ed767239f0e85880f416fc384
External References: https://talosintelligence.com/vulnerability_reports/TALOS-2019-0887
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:1913 https://access.redhat.com/errata/RHSA-2020:1913
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2019-5094
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2020:4011 https://access.redhat.com/errata/RHSA-2020:4011