Timing attack in Mozilla NSS library



Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-12399
CWE-ID CWE-362
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
 Mozilla NSS
Universal components / Libraries / Libraries used by multiple products

Vendor Mozilla

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Race condition

EUVDB-ID: #VU28522

Risk: Medium

CVSSv4.0: 6.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2020-12399

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 gain access to sensitive information.

The vulnerability exists due to time differences in Mozilla NSS library during the process of generating a DSA signature, the nonce value 'k' is not padded, exposing the bit length. Combined with other techniques, this can result in the recovery of the DSA private key.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Mozilla NSS: 3.40 - 3.52.1

CPE2.3 External links

https://www.mozilla.org/en-US/security/advisories/mfsa2020-20/
https://bugzilla.mozilla.org/show_bug.cgi?id=1631576
https://bugzilla.redhat.com/show_bug.cgi?id=1826177


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

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.



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