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amazonAmazonALAS-2023-1838
HistorySep 27, 2023 - 10:15 p.m.

Important: kernel

2023-09-2722:15:00
alas.aws.amazon.com
17
kernel
xfrm subsystem
netfilter
race condition
privilege escalation
use-after-free

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

AI Score

7

Confidence

High

EPSS

0.001

Percentile

21.8%

Issue Overview:

2024-03-13: CVE-2023-4244 was added to this advisory.

2023-10-25: CVE-2023-45871 was added to this advisory.

2023-10-12: CVE-2023-42753 was added to this advisory.

2023-10-12: CVE-2023-39192 was added to this advisory.

2023-10-12: CVE-2023-39194 was added to this advisory.

2023-10-12: CVE-2023-42755 was added to this advisory.

2023-10-12: CVE-2023-39193 was added to this advisory.

A flaw was found in the Linux kernel’s IP framework for transforming packets (XFRM subsystem). This issue may allow a malicious user with CAP_NET_ADMIN privileges to directly dereference a NULL pointer in xfrm_update_ae_params(), leading to a possible kernel crash and denial of service. (CVE-2023-3772)

netfilter: xt_u32: validate user space input

NOTE: https://www.zerodayinitiative.com/advisories/ZDI-23-1490/
NOTE: https://git.kernel.org/linus/69c5d284f67089b4750d28ff6ac6f52ec224b330 (6.6-rc1) (CVE-2023-39192)

netfilter: xt_sctp: validate the flag_info count

NOTE: https://www.zerodayinitiative.com/advisories/ZDI-23-1491/
NOTE: https://git.kernel.org/linus/e99476497687ef9e850748fe6d232264f30bc8f9 (6.6-rc1) (CVE-2023-39193)

net: xfrm: Fix xfrm_address_filter OOB read

NOTE: https://www.zerodayinitiative.com/advisories/ZDI-23-1492/
NOTE: https://git.kernel.org/linus/dfa73c17d55b921e1d4e154976de35317e43a93a (6.5-rc7) (CVE-2023-39194)

A use-after-free vulnerability in the Linux kernel’s net/sched: cls_fw component can be exploited to achieve local privilege escalation.

When fw_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free.

We recommend upgrading past commit 76e42ae831991c828cffa8c37736ebfb831ad5ec. (CVE-2023-4207)

A use-after-free vulnerability in the Linux kernel’s netfilter: nf_tables component can be exploited to achieve local privilege escalation.

Due to a race condition between nf_tables netlink control plane transaction and nft_set element garbage collection, it is possible to underflow the reference counter causing a use-after-free vulnerability.

We recommend upgrading past commit 3e91b0ebd994635df2346353322ac51ce84ce6d8. (CVE-2023-4244)

The upstream commit describes this issue as follows:

The missing IP_SET_HASH_WITH_NET0 macro in ip_set_hash_netportnet can lead to the use of wrong CIDR_POS(c) for calculating array offsets, which can lead to integer underflow. As a result, it leads to slab out-of-bound access. (CVE-2023-42753)

A flaw was found in rsvp_change(). The root cause is an slab-out-of-bound access, but since the offset to the original pointer is an unsign int fully controlled by users, the behavior is usually a wild pointer access. (CVE-2023-42755)

An issue was discovered in drivers/net/ethernet/intel/igb/igb_main.c in the IGB driver in the Linux kernel before 6.5.3. A buffer size may not be adequate for frames larger than the MTU. (CVE-2023-45871)

A use-after-free vulnerability in the Linux kernel’s af_unix component can be exploited to achieve local privilege escalation.

The unix_stream_sendpage() function tries to add data to the last skb in the peer’s recv queue without locking the queue. Thus there is a race where unix_stream_sendpage() could access an skb locklessly that is being released by garbage collection, resulting in use-after-free.

We recommend upgrading past commit 790c2f9d15b594350ae9bca7b236f2b1859de02c. (CVE-2023-4622)

A use-after-free vulnerability in the Linux kernel’s net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation.

If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free.

We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f. (CVE-2023-4623)

A use-after-free vulnerability in the Linux kernel’s net/sched: sch_qfq component can be exploited to achieve local privilege escalation.

When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfq_dequeue() due to the incorrect .peek handler of sch_plug and lack of error checking in agg_dequeue().

We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8. (CVE-2023-4921)

Affected Packages:

kernel

Issue Correction:
Run yum update kernel to update your system.

New Packages:

i686:  
    kernel-tools-4.14.326-171.539.amzn1.i686  
    perf-4.14.326-171.539.amzn1.i686  
    kernel-headers-4.14.326-171.539.amzn1.i686  
    kernel-4.14.326-171.539.amzn1.i686  
    kernel-debuginfo-4.14.326-171.539.amzn1.i686  
    kernel-debuginfo-common-i686-4.14.326-171.539.amzn1.i686  
    kernel-tools-debuginfo-4.14.326-171.539.amzn1.i686  
    kernel-devel-4.14.326-171.539.amzn1.i686  
    perf-debuginfo-4.14.326-171.539.amzn1.i686  
    kernel-tools-devel-4.14.326-171.539.amzn1.i686  
  
src:  
    kernel-4.14.326-171.539.amzn1.src  
  
x86_64:  
    kernel-tools-debuginfo-4.14.326-171.539.amzn1.x86_64  
    perf-4.14.326-171.539.amzn1.x86_64  
    kernel-debuginfo-4.14.326-171.539.amzn1.x86_64  
    kernel-tools-devel-4.14.326-171.539.amzn1.x86_64  
    kernel-4.14.326-171.539.amzn1.x86_64  
    kernel-tools-4.14.326-171.539.amzn1.x86_64  
    kernel-headers-4.14.326-171.539.amzn1.x86_64  
    kernel-devel-4.14.326-171.539.amzn1.x86_64  
    kernel-debuginfo-common-x86_64-4.14.326-171.539.amzn1.x86_64  
    perf-debuginfo-4.14.326-171.539.amzn1.x86_64  

Additional References

Red Hat: CVE-2023-3772, CVE-2023-39192, CVE-2023-39193, CVE-2023-39194, CVE-2023-4207, CVE-2023-4244, CVE-2023-42753, CVE-2023-42755, CVE-2023-45871, CVE-2023-4622, CVE-2023-4623, CVE-2023-4921

Mitre: CVE-2023-3772, CVE-2023-39192, CVE-2023-39193, CVE-2023-39194, CVE-2023-4207, CVE-2023-4244, CVE-2023-42753, CVE-2023-42755, CVE-2023-45871, CVE-2023-4622, CVE-2023-4623, CVE-2023-4921

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

AI Score

7

Confidence

High

EPSS

0.001

Percentile

21.8%