Debian update for linux



Published: 2021-07-22 | Updated: 2021-12-24
Risk Medium
Patch available YES
Number of vulnerabilities 4
CVE-ID CVE-2020-36311
CVE-2021-3609
CVE-2021-33909
CVE-2021-34693
CWE-ID CWE-264
CWE-362
CWE-190
CWE-908
Exploitation vector Local
Public exploit Public exploit code for vulnerability #2 is available.
Public exploit code for vulnerability #3 is available.
Vulnerable software
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linux (Debian package)
Operating systems & Components / Operating system package or component

Vendor Debian

Security Bulletin

This security bulletin contains information about 4 vulnerabilities.

1) Permissions, Privileges, and Access Controls

EUVDB-ID: #VU55262

Risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-36311

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a local user to perform a denial of service attack.

The vulnerability exists due to an error in arch/x86/kvm/svm/sev.c in Linux kernel, which allows soft lockup by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions).

Mitigation

Update linux package to version 4.19.194-3.

Vulnerable software versions

linux (Debian package): 4.19.5-1~exp1 - 4.19.160-2


CPE2.3 External links

http://www.debian.org/security/2021/dsa-4941

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Race condition

EUVDB-ID: #VU54292

Risk: Medium

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-3609

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition in the CAN BCM networking protocol (net/can/bcm.c) in the Linux kernel ranging from version 2.6.25 to mainline 5.13-rc6. A local user can exploit the race and gain unauthorized access to sensitive information and escalate privileges on the system.

Mitigation

Update linux package to version 4.19.194-3.

Vulnerable software versions

linux (Debian package): 4.19.5-1~exp1 - 4.19.160-2


CPE2.3 External links

http://www.debian.org/security/2021/dsa-4941

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

3) Integer overflow

EUVDB-ID: #VU55143

Risk: Medium

CVSSv3.1: 7.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2021-33909

CWE-ID: CWE-190 - Integer Overflow or Wraparound

Exploit availability: Yes

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to integer overflow during size_t-to-int conversion when creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB. An unprivileged local user can write up to 10-byte string to an offset of exactly -2GB-10B below the beginning of a vmalloc()ated kernel buffer.

Successful exploitation of vulnerability may allow an attacker to exploit the our-of-bounds write vulnerability to execute arbitrary code with root privileges.

Mitigation

Update linux package to version 4.19.194-3.

Vulnerable software versions

linux (Debian package): 4.19.5-1~exp1 - 4.19.160-2


CPE2.3 External links

http://www.debian.org/security/2021/dsa-4941

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

4) Use of uninitialized resource

EUVDB-ID: #VU55263

Risk: Low

CVSSv3.1: 2.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-34693

CWE-ID: CWE-908 - Use of Uninitialized Resource

Exploit availability: No

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to net/can/bcm.c in the Linux kernel through 5.12.10 allows local users to obtain sensitive information from kernel stack memory because parts of a data structure are uninitialized.

Mitigation

Update linux package to version 4.19.194-3.

Vulnerable software versions

linux (Debian package): 4.19.5-1~exp1 - 4.19.160-2


CPE2.3 External links

http://www.debian.org/security/2021/dsa-4941

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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