Executive Summary

Informations
Name CVE-2023-52443 First vendor Publication 2024-02-22
Vendor Cve Last vendor Modification 2024-03-14

Security-Database Scoring CVSS v3

Cvss vector : CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Overall CVSS Score 5.5
Base Score 5.5 Environmental Score 5.5
impact SubScore 3.6 Temporal Score 5.5
Exploitabality Sub Score 1.8
 
Attack Vector Local Attack Complexity Low
Privileges Required Low User Interaction None
Scope Unchanged Confidentiality Impact None
Integrity Impact None Availability Impact High
Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score N/A Attack Range N/A
Cvss Impact Score N/A Attack Complexity N/A
Cvss Expoit Score N/A Authentication N/A
Calculate full CVSS 2.0 Vectors scores

Detail

In the Linux kernel, the following vulnerability has been resolved:

apparmor: avoid crash when parsed profile name is empty

When processing a packed profile in unpack_profile() described like

"profile :ns::samba-dcerpcd /usr/lib*/samba/{,samba/}samba-dcerpcd {...}"

a string ":samba-dcerpcd" is unpacked as a fully-qualified name and then passed to aa_splitn_fqname().

aa_splitn_fqname() treats ":samba-dcerpcd" as only containing a namespace. Thus it returns NULL for tmpname, meanwhile tmpns is non-NULL. Later aa_alloc_profile() crashes as the new profile name is NULL now.

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 6 PID: 1657 Comm: apparmor_parser Not tainted 6.7.0-rc2-dirty #16 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-3-gd478f380-rebuilt.opensuse.org 04/01/2014 RIP: 0010:strlen+0x1e/0xa0 Call Trace:

? strlen+0x1e/0xa0
aa_policy_init+0x1bb/0x230
aa_alloc_profile+0xb1/0x480
unpack_profile+0x3bc/0x4960
aa_unpack+0x309/0x15e0
aa_replace_profiles+0x213/0x33c0
policy_update+0x261/0x370
profile_replace+0x20e/0x2a0
vfs_write+0x2af/0xe00
ksys_write+0x126/0x250
do_syscall_64+0x46/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76
---[ end trace 0000000000000000 ]--- RIP: 0010:strlen+0x1e/0xa0

It seems such behaviour of aa_splitn_fqname() is expected and checked in other places where it is called (e.g. aa_remove_profiles). Well, there is an explicit comment "a ns name without a following profile is allowed" inside.

AFAICS, nothing can prevent unpacked "name" to be in form like ":samba-dcerpcd" - it is passed from userspace.

Deny the whole profile set replacement in such case and inform user with EPROTO and an explaining message.

Found by Linux Verification Center (linuxtesting.org).

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-52443

CWE : Common Weakness Enumeration

% Id Name
100 % CWE-476 NULL Pointer Dereference

CPE : Common Platform Enumeration

TypeDescriptionCount
Application 8
Os 3561

Sources (Detail)

https://git.kernel.org/stable/c/0a12db736edbb4933e4274932aeea594b5876fa4
https://git.kernel.org/stable/c/1d8e62b5569cc1466ceb8a7e4872cf10160a9dcf
https://git.kernel.org/stable/c/55a8210c9e7d21ff2644809699765796d4bfb200
https://git.kernel.org/stable/c/5c0392fdafb0a2321311900be83ffa572bef8203
https://git.kernel.org/stable/c/5ff00408e5029d3550ee77f62dc15f1e15c47f87
https://git.kernel.org/stable/c/77ab09b92f16c8439a948d1af489196953dc4a0e
https://git.kernel.org/stable/c/9286ee97aa4803d99185768735011d0d65827c9e
https://git.kernel.org/stable/c/9d4fa5fe2b1d56662afd14915a73b4d0783ffa45
Source Url

Alert History

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Date Informations
2024-03-15 00:27:29
  • Multiple Updates
2024-02-23 00:27:23
  • Multiple Updates
2024-02-22 21:27:25
  • First insertion