CVE-2015-7764: Lemur Lemur Uses Static IV Per Vulnerability

HIGH
Advisory Identifier: GHSA-chg9-3c3p-ch23
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CVSS 7.5
CWE-331
Published
Advisory Summary

CVE-2015-7764 is a HIGH (CVSS 7.5) lemur uses static iv per vulnerability (CWE-331: Insufficient Entropy) affecting Lemur libraries in the PyPI ecosystem. The issue involves lemur uses static iv per key. Remediation is available by upgrading affected packages to version 0.1.5.

CVE-2015-7764 at a Glance

CVE Identifier CVE-2015-7764
GHSA Identifier GHSA-chg9-3c3p-ch23
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-331: Insufficient Entropy
Affected Product Lemur
Package Ecosystem PyPI
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-2015-7764

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

lemur fixed: 0.1.5 
pip install lemur>=0.1.5
Verify Direct and Transitive Dependencies

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

pip show lemur

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2015-7764, inspect your installed packages using pip:

pip show lemur

Analyze the terminal output to locate any version of Lemur in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.1.5), your application is affected.

Note: The pip show lemur command checks currently installed packages in your active Python environment.

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 Lemur, 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

Lemur 0.1.4 does not use sufficient entropy in its IV when encrypting AES in CBC mode.

CVE-2015-7764 Affected Lemur Versions

1 component(s)
Fixed Versions:
0.1.5
Product / Package Ecosystem Affected Versions Fixed Version
lemur
pypi/lemur
PyPI
< 0.1.5
0.1.5

References

NVD — CVE-2015-7764 NVD
https://nvd.nist.gov/vuln/detail/CVE-2015-7764
Lemur Source Repository REPOSITORY
https://github.com/Netflix/lemur/issues/117
Lemur Source Repository REPOSITORY
https://github.com/kvesteri/sqlalchemy-utils/issues/166
Security Fix Commit FIX COMMIT
https://github.com/Netflix/lemur/commit/394e18f76e5eb534d95160945ebc231ec3b4c794
Lemur Source Repository REPOSITORY
https://github.com/Netflix/lemur
Lemur Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/lemur/PYSEC-2017-50.yaml
Lemur Security Information SECURITY
http://www.openwall.com/lists/oss-security/2015/10/20/3

Frequently Asked Questions

What is CVE-2015-7764?
CVE-2015-7764 is a security vulnerability in Lemur involving Lemur uses static IV per key under CWE-331: Insufficient Entropy.
Which Lemur versions are affected?
Affected versions include releases prior to 0.1.5 across affected packages: lemur.
What version fixes CVE-2015-7764?
Upgrading to 0.1.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is lemur affected?
Yes, lemur is affected in releases prior to 0.1.5. Upgrade your dependency to 0.1.5 or later.
What is the CVSS score of CVE-2015-7764?
CVE-2015-7764 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-2015-7764?
CVE-2015-7764 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 PyPI dependencies for CVE-2015-7764?
Run the dependency tree command: 'pip show lemur'. 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-chg9-3c3p-ch23",
  "modified" : "2024-09-30T16:13:21Z",
  "published" : "2022-05-13T01:30:21Z",
  "aliases" : [ "CVE-2015-7764" ],
  "summary" : "Lemur uses static IV per key",
  "details" : "Lemur 0.1.4 does not use sufficient entropy in its IV when encrypting AES in CBC mode.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "lemur"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.1.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2015-7764"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Netflix/lemur/issues/117"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/kvesteri/sqlalchemy-utils/issues/166"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/Netflix/lemur/commit/394e18f76e5eb534d95160945ebc231ec3b4c794"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/Netflix/lemur"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/lemur/PYSEC-2017-50.yaml"
  }, {
    "type" : "WEB",
    "url" : "http://www.openwall.com/lists/oss-security/2015/10/20/3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-331" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-29T14:49:35Z",
    "nvd_published_at" : "2017-08-09T16:29:00Z"
  }
}