// For flags

CVE-2020-12399

nss: Timing attack on DSA signature generation

Severity Score

4.4
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

NSS has shown timing differences when performing DSA signatures, which was exploitable and could eventually leak private keys. This vulnerability affects Thunderbird < 68.9.0, Firefox < 77, and Firefox ESR < 68.9.

NSS ha mostrado diferencias de sincronización cuando se llevan a cabo firmas DSA, que fue explotable y eventualmente podría filtrar claves privadas. Esta vulnerabilidad afecta a Thunderbird versiones anteriores a 68.9.0, Firefox versiones anteriores a 77 y Firefox ESR versiones anteriores a 68.9

A flaw was found in the DSA signature generation function in nss. 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. The highest threat from this vulnerability is to data confidentiality.

Multiple security issues were discovered in Thunderbird. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, or execute arbitrary code. It was discovered that Thunderbird would continue an unencrypted connection when configured to use STARTTLS for IMAP if the server responded with PREAUTH. A remote attacker could potentially exploit this to perform a person-in-the-middle attack in order to obtain sensitive information. Various other issues were also addressed.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Local
Attack Complexity
High
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2020-04-28 CVE Reserved
  • 2020-06-05 CVE Published
  • 2024-08-04 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-203: Observable Discrepancy
  • CWE-327: Use of a Broken or Risky Cryptographic Algorithm
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Mozilla
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Firefox
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< 77.0
Search vendor "Mozilla" for product "Firefox" and version " < 77.0"
-
Affected
Mozilla
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Firefox Esr
Search vendor "Mozilla" for product "Firefox Esr"
< 68.9.0
Search vendor "Mozilla" for product "Firefox Esr" and version " < 68.9.0"
-
Affected
Mozilla
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Thunderbird
Search vendor "Mozilla" for product "Thunderbird"
< 68.9.0
Search vendor "Mozilla" for product "Thunderbird" and version " < 68.9.0"
-
Affected
Debian
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Debian Linux
Search vendor "Debian" for product "Debian Linux"
9.0
Search vendor "Debian" for product "Debian Linux" and version "9.0"
-
Affected