7 CVE-2024-43882

Patch

In the Linux kernel, the following vulnerability has been resolved: exec: Fix ToCToU between perm check and set-uid/gid usage When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges. For example, if a file could change permissions from executable and not set-id: ---------x 1 root root 16048 Aug 7 13:16 target to set-id and non-executable: ---S------ 1 root root 16048 Aug 7 13:16 target it is possible to gain root privileges when execution should have been disallowed. While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root: -rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target becomes: -rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root". Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal.
https://nvd.nist.gov/vuln/detail/CVE-2024-43882

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch

https://git.kernel.org/stable/c/15469d46ba34559bfe7e3de6659115778c624759 Patch
https://git.kernel.org/stable/c/368f6985d46657b8b466a421dddcacd4051f7ada Patch
https://git.kernel.org/stable/c/90dfbba89ad4f0d9c9744ecbb1adac4aa2ff4f3e Patch
https://git.kernel.org/stable/c/9b424c5d4130d56312e2a3be17efb0928fec4d64 Patch
https://git.kernel.org/stable/c/d2a2a4714d80d09b0f8eb6438ab4224690b7121e Patch
https://git.kernel.org/stable/c/d5c3c7e26275a2d83b894d30f7582a42853a958f Patch
https://git.kernel.org/stable/c/f50733b45d865f91db90919f8311e2127ce5a0cb Patch
https://git.kernel.org/stable/c/f6cfc6bcfd5e1cf76115b6450516ea4c99897ae1 Patch

CPE

cpe	start	end
Configuration 1
cpe:2.3:o:linux:linux_kernel::::::::		< 4.19.320
cpe:2.3:o:linux:linux_kernel::::::::	>= 4.20	< 5.4.282
cpe:2.3:o:linux:linux_kernel::::::::	>= 5.5	< 5.10.224
cpe:2.3:o:linux:linux_kernel::::::::	>= 5.11	< 5.15.165
cpe:2.3:o:linux:linux_kernel::::::::	>= 5.16	< 6.1.106
cpe:2.3:o:linux:linux_kernel::::::::	>= 6.2	< 6.6.47
cpe:2.3:o:linux:linux_kernel::::::::	>= 6.7	< 6.10.6
cpe:2.3:o:linux:linux_kernel:6.11:rc1::::::
cpe:2.3:o:linux:linux_kernel:6.11:rc2::::::
cpe:2.3:o:linux:linux_kernel:6.11:rc3::::::

REMEDIATION

Patch

Url
https://git.kernel.org/stable/c/15469d46ba34559bfe7e3de6659115778c624759
https://git.kernel.org/stable/c/368f6985d46657b8b466a421dddcacd4051f7ada
https://git.kernel.org/stable/c/90dfbba89ad4f0d9c9744ecbb1adac4aa2ff4f3e
https://git.kernel.org/stable/c/9b424c5d4130d56312e2a3be17efb0928fec4d64
https://git.kernel.org/stable/c/d2a2a4714d80d09b0f8eb6438ab4224690b7121e
https://git.kernel.org/stable/c/d5c3c7e26275a2d83b894d30f7582a42853a958f
https://git.kernel.org/stable/c/f50733b45d865f91db90919f8311e2127ce5a0cb
https://git.kernel.org/stable/c/f6cfc6bcfd5e1cf76115b6450516ea4c99897ae1

EXPLOITS

Exploit-db.com

id	description	date
No known exploits

POC Github

Url
No known exploits

Other Nist (github, ...)

Url
No known exploits

CAPEC

Common Attack Pattern Enumerations and Classifications

id	description	severity
27	Leveraging Race Conditions via Symbolic Links This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to them. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file they will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file. [Verify that target host's platform supports symbolic links.] This attack pattern is only applicable on platforms that support symbolic links. [Examine application's file I/O behavior] Analyze the application's file I/O behavior to determine where it stores files, as well as the operations it performs to read/write files. [Verify ability to write to filesystem] The attacker verifies ability to write to the target host's file system. [Replace file with a symlink to a sensitive system file.] Between the time that the application checks to see if a file exists (or if the user has access to it) and the time the application actually opens the file, the attacker replaces the file with a symlink to a sensitive system file.	High
29	Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. A typical example is file access. The adversary can leverage a file access race condition by "running the race", meaning that they would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the adversary could replace or modify the file, causing the application to behave unexpectedly. The adversary explores to gauge what level of access they have. The adversary confirms access to a resource on the target host. The adversary confirms ability to modify the targeted resource. The adversary decides to leverage the race condition by "running the race", meaning that they would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the adversary can replace the resource and cause an escalation of privilege.	High

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7 CVE-2024-43882

Patch

Categories

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch

CPE

REMEDIATION

Patch

EXPLOITS

Exploit-db.com

POC Github

Other Nist (github, ...)

CAPEC

Cybersecurity needs ?