CVE-2021-44556 Vulnerability Analysis & Exploit Details

CVE-2021-44556
Vulnerability Scoring

9.1
/10
Critical Risk

As a catastrophic security flaw, CVE-2021-44556 has severe implications, demanding immediate intervention.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-44556 Details

Status: Modified

Last updated: 🕡 21 Nov 2024, 06:31 UTC
Originally published on: 🕛 08 Dec 2021, 12:15 UTC

Time between publication and last update: 1078 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

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

CVE-2021-44556 Vulnerability Summary

CVE-2021-44556: National Library of the Netherlands digger < 6697d1269d981e35e11f240725b16401b5ce3db5 is affected by a XML External Entity (XXE) vulnerability. Since XML parsing resolves external entities, a malicious XML stream could leak internal files and/or cause a DoS.

Assessing the Risk of CVE-2021-44556

Access Complexity Graph

The exploitability of CVE-2021-44556 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-2021-44556

With low attack complexity and no required privileges, CVE-2021-44556 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

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-2021-44556, 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-2021-44556, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2021-44556 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: None
    CVE-2021-44556 poses no threat to data integrity.
  • Availability: High
    CVE-2021-44556 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: 0.217% (probability of exploit)

EPSS Percentile: 60.21% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 39.79% of others.

CVE-2021-44556 References

External References

CWE Common Weakness Enumeration

CWE-611

CAPEC Common Attack Pattern Enumeration and Classification

  • Data Serialization External Entities Blowup CAPEC-221 This attack takes advantage of the entity replacement property of certain data serialization languages (e.g., XML, YAML, etc.) where the value of the replacement is a URI. A well-crafted file could have the entity refer to a URI that consumes a large amount of resources to create a denial of service condition. This can cause the system to either freeze, crash, or execute arbitrary code depending on the URI.

Vulnerable Configurations

  • cpe:2.3:a:kb:digger:-:*:*:*:*:*:*:*
    cpe:2.3:a:kb:digger:-:*:*:*:*:*:*:*

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