CVE-2020-28924: Github.com/rclone/rclone Use Of Cryptographically Weak Pseudo-Random Vulnerability

HIGH
Advisory Identifier: GHSA-rmw5-xpg9-jr29
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CVSS 7.5
CWE-331 CWE-338
Published
Advisory Summary

CVE-2020-28924 is a HIGH (CVSS 7.5) use of cryptographically weak pseudo-random vulnerability (CWE-331: Insufficient Entropy) affecting Github.com/rclone/rclone libraries in the Go ecosystem. The issue involves use of cryptographically weak pseudo-random number generator in rclone. Remediation is available by upgrading affected packages to version 1.53.3.

CVE-2020-28924 at a Glance

CVE Identifier CVE-2020-28924
GHSA Identifier GHSA-rmw5-xpg9-jr29
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-331: Insufficient Entropy
Affected Product Github.com/rclone/rclone
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2020-28924

To remediate this vulnerability, upgrade all affected Github.com/rclone/rclone dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/rclone/rclone fixed: 1.53.3 
Upgrade github.com/rclone/rclone to 1.53.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/rclone/rclone

How to Check if You Are Affected

To determine whether your application is affected by CVE-2020-28924, inspect your project dependencies for Github.com/rclone/rclone:

inspect dependencies for github.com/rclone/rclone

Analyze the terminal output to locate any version of Github.com/rclone/rclone in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.53.3), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-331: Insufficient Entropy, where the product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others. In Github.com/rclone/rclone, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

An issue was discovered in Rclone before 1.53.3. Due to the use of a weak random number generator, the password generator has been producing weak passwords with much less entropy than advertised. The suggested passwords depend deterministically on the time the second rclone was started. This limits the entropy of the passwords enormously. These passwords are often used in the crypt backend for encryption of data. It would be possible to make a dictionary of all possible passwords with about 38 million entries per password length. This would make decryption of secret material possible with a plausible amount of effort. NOTE: all passwords generated by affected versions should be changed.

CVE-2020-28924 Affected Github.com/rclone/rclone Versions

1 component(s)
Fixed Versions:
1.53.3
Product / Package Ecosystem Affected Versions Fixed Version
github.com/rclone/rclone
golang/github.com/rclone/rclone
Go
< 1.53.3
1.53.3

References

NVD — CVE-2020-28924 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-28924
Github.com/rclone/rclone Source Repository REPOSITORY
https://github.com/rclone/rclone/issues/4783
Github.com/rclone/rclone Source Repository REPOSITORY
https://github.com/rclone/rclone
lists.fedoraproject.org/archives/list/packa... WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIFT24Q6EFXLQZ24AER2QGFFZLMIPCD
Github.com/rclone/rclone Security Information SECURITY
https://security.gentoo.org/glsa/202107-14

Frequently Asked Questions

What is CVE-2020-28924?
CVE-2020-28924 is a security vulnerability in Github.com/rclone/rclone involving Use of Cryptographically Weak Pseudo-Random Number Generator in Rclone under CWE-331: Insufficient Entropy.
Which Github.com/rclone/rclone versions are affected?
Affected versions include releases prior to 1.53.3 across affected packages: github.com/rclone/rclone.
What version fixes CVE-2020-28924?
Upgrading to 1.53.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/rclone/rclone affected?
Yes, github.com/rclone/rclone is affected in releases prior to 1.53.3. Upgrade your dependency to 1.53.3 or later.
What is the CVSS score of CVE-2020-28924?
CVE-2020-28924 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2020-28924?
CVE-2020-28924 is classified under CWE-331: Insufficient Entropy (The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.).
How can I check Go dependencies for CVE-2020-28924?
Run the dependency tree command: 'inspect dependencies for github.com/rclone/rclone'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rmw5-xpg9-jr29",
  "modified" : "2022-04-27T20:30:31Z",
  "published" : "2021-06-10T17:23:21Z",
  "aliases" : [ "CVE-2020-28924" ],
  "summary" : "Use of Cryptographically Weak Pseudo-Random Number Generator in Rclone",
  "details" : "An issue was discovered in Rclone before 1.53.3. Due to the use of a weak random number generator, the password generator has been producing weak passwords with much less entropy than advertised. The suggested passwords depend deterministically on the time the second rclone was started. This limits the entropy of the passwords enormously. These passwords are often used in the crypt backend for encryption of data. It would be possible to make a dictionary of all possible passwords with about 38 million entries per password length. This would make decryption of secret material possible with a plausible amount of effort. NOTE: all passwords generated by affected versions should be changed.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/rclone/rclone"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.53.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-28924"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rclone/rclone/issues/4783"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rclone/rclone"
  }, {
    "type" : "WEB",
    "url" : "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIFT24Q6EFXLQZ24AER2QGFFZLMIPCD"
  }, {
    "type" : "WEB",
    "url" : "https://security.gentoo.org/glsa/202107-14"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-331", "CWE-338" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-06-09T14:47:19Z",
    "nvd_published_at" : "2020-11-19T20:15:00Z"
  }
}