CVE-2021-3997 Vulnerability Analysis & Exploit Details

CVE-2021-3997
Vulnerability Scoring

5.5
/10
Significant Risk

Security assessments indicate that CVE-2021-3997 presents a notable risk, potentially requiring prompt mitigation.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Local
    Vulnerability requires local system access.
  • Privileges Required: Low
    Some privileges are necessary to exploit the vulnerability.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-3997 Details

Status: Modified

Last updated: 🕕 21 Nov 2024, 06:23 UTC
Originally published on: 🕗 23 Aug 2022, 20:15 UTC

Time between publication and last update: 820 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVE-2021-3997 Vulnerability Summary

CVE-2021-3997: A flaw was found in systemd. An uncontrolled recursion in systemd-tmpfiles may lead to a denial of service at boot time when too many nested directories are created in /tmp.

Assessing the Risk of CVE-2021-3997

Access Complexity Graph

The exploitability of CVE-2021-3997 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2021-3997

CVE-2021-3997 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2021-3997, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2021-3997, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: None
    CVE-2021-3997 has no significant impact on data confidentiality.
  • Integrity: None
    CVE-2021-3997 poses no threat to data integrity.
  • Availability: High
    CVE-2021-3997 can disrupt system operations, potentially causing complete denial of service (DoS).

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 0.056% (probability of exploit)

EPSS Percentile: 26.87% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 73.13% of others.

CVE-2021-3997 References

External References

CWE Common Weakness Enumeration

CWE-674

CAPEC Common Attack Pattern Enumeration and Classification

  • Serialized Data with Nested Payloads CAPEC-230 Applications often need to transform data in and out of a data format (e.g., XML and YAML) by using a parser. It may be possible for an adversary to inject data that may have an adverse effect on the parser when it is being processed. Many data format languages allow the definition of macro-like structures that can be used to simplify the creation of complex structures. By nesting these structures, causing the data to be repeatedly substituted, an adversary can cause the parser to consume more resources while processing, causing excessive memory consumption and CPU utilization.
  • Oversized Serialized Data Payloads CAPEC-231 An adversary injects oversized serialized data payloads into a parser during data processing to produce adverse effects upon the parser such as exhausting system resources and arbitrary code execution.

Vulnerable Configurations

  • cpe:2.3:a:systemd_project:systemd:240:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:240:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:241:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:241:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:241:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:241:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:241:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:241:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:242:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:242:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:242:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:242:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:242:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:242:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:242:rc3:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:242:rc3:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:242:rc4:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:242:rc4:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:243:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:243:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:244:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:244:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:244:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:244:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:245:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:245:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:245:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:245:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:245:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:245:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:246:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:246:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:246.15:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:246.15:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:246:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:246:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:246:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:246:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:247:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:247:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:247.8:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:247.8:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:247:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:247:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:247:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:247:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.1:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.1:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.2:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.2:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.3:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.3:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.4:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.4:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.5:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.5:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.6:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.6:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.7:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.7:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.8:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.8:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.9:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.9:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248.10:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248.10:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248:rc3:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248:rc3:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:248:rc4:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:248:rc4:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.1:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.1:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.2:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.2:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.3:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.3:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.4:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.4:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.5:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.5:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.6:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.6:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.7:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.7:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.8:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.8:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.9:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.9:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.10:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.10:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.11:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.11:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249.12:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249.12:*:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249:rc1:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249:rc1:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249:rc2:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249:rc2:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:249:rc3:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:249:rc3:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:250:-:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:250:-:*:*:*:*:*:*
  • cpe:2.3:a:systemd_project:systemd:250.1:*:*:*:*:*:*:*
    cpe:2.3:a:systemd_project:systemd:250.1:*:*:*:*:*:*:*
  • cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
    cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
  • cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
    cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
    cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
    cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
  • cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
    cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

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