CyberSecBulletin
CVE-2023-52603NVD status: Modified

Linux: Improper Validation of Array Index

Published Updated By the CyberSecBulletin desk

CVE-2023-52603 is a high-severity improper validation of array index vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions e30b52a2ea3d1e0aaee68096957cf90a2f4ec5af, fd3486a893778770557649fe28afa5e463d4ed07, 7aa33854477d9c346f5560a1a1fcb3fe7783e2a8 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to e30b52a2ea3d1e0aaee68096957cf90a2f4ec5af or fd3486a893778770557649fe28afa5e463d4ed07 or 7aa33854477d9c346f5560a1a1fcb3fe7783e2a8 or e4ce01c25ccbea02a09a5291c21749b1fc358e39, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 4.19.307 or 5.4.269 or 5.10.210 or 5.15.149, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, e30b52a2ea3d1e0aaee68096957cf90a2f4ec5af; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, fd3486a893778770557649fe28afa5e463d4ed07; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 7aa33854477d9c346f5560a1a1fcb3fe7783e2a8; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, e4ce01c25ccbea02a09a5291c21749b1fc358e39; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, e4cbc857d75d4e22a1f75446e7480b1f305d8d60; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, edff092a59260bf0b0a2eba219cb3da6372c2f9f; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 6e2902ecc77e9760a9fc447f56d598383e2372d2; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 27e56f59bab5ddafbcfe69ad7a4a6ea1279c1b16; and 1 more rangese30b52a2ea3d1e0aaee68096957cf90a2f4ec5af, fd3486a893778770557649fe28afa5e463d4ed07, 7aa33854477d9c346f5560a1a1fcb3fe7783e2a8, e4ce01c25ccbea02a09a5291c21749b1fc358e39, e4cbc857d75d4e22a1f75446e7480b1f305d8d60, edff092a59260bf0b0a2eba219cb3da6372c2f9f
LinuxLinux Kernelbefore 4.19.307; 4.20 up to, but not including, 5.4.269; 5.5 up to, but not including, 5.10.210; 5.11 up to, but not including, 5.15.149; 5.16 up to, but not including, 6.1.77; 6.2 up to, but not including, 6.6.16; 6.7 up to, but not including, 6.7.44.19.307, 5.4.269, 5.10.210, 5.15.149, 6.1.77, 6.6.16

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.8HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: UBSAN: array-index-out-of-bounds in dtSplitRoot Syzkaller reported the following issue: oop0: detected capacity change from 0 to 32768 UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:1971:9 index -2 is out of range for type 'struct dtslot [128]' CPU: 0 PID: 3613 Comm: syz-executor270 Not tainted 6.0.0-syzkaller-09423-g493ffd6605b2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:151 [inline] __ubsan_handle_out_of_bounds+0xdb/0x130 lib/ubsan.c:283 dtSplitRoot+0x8d8/0x1900 fs/jfs/jfs_dtree.c:1971 dtSplitUp fs/jfs/jfs_dtree.c:985 [inline] dtInsert+0x1189/0x6b80 fs/jfs/jfs_dtree.c:863 jfs_mkdir+0x757/0xb00 fs/jfs/namei.c:270 vfs_mkdir+0x3b3/0x590 fs/namei.c:4013 do_mkdirat+0x279/0x550 fs/namei.c:4038 __do_sys_mkdirat fs/namei.c:4053 [inline] __se_sys_mkdirat fs/namei.c:4051 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4051 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fcdc0113fd9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffeb8bc67d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fcdc0113fd9 RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003 RBP: 00007fcdc00d37a0 R08: 0000000000000000 R09: 00007fcdc00d37a0 R10: 00005555559a72c0 R11: 0000000000000246 R12: 00000000f8008000 R13: 0000000000000000 R14: 00083878000000f8 R15: 0000000000000000 </TASK> The issue is caused when the value of fsi becomes less than -1. The check to break the loop when fsi value becomes -1 is present but syzbot was able to produce value less than -1 which cause the error. This patch simply add the change for the values less than 0. The patch is tested via syzbot.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Validation of Array Index

The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

How developers prevent this class of flaw

  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, Ada allows the programmer to constrain the values of a variable and languages such as Java and Ruby will allow the programmer to handle exceptions when an out-of-bounds index is accessed.
  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment. For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND.

More Improper Validation of Array Index vulnerabilities (CWE-129)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Validation of Array Index vulnerabilities

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