CVE-2021-21557 Vulnerability Analysis & Exploit Details

CVE-2021-21557
Vulnerability Scoring

8.1
/10
Severe Risk

Cybersecurity professionals consider CVE-2021-21557 an immediate threat requiring urgent 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: High
    High-level privileges are required for exploitation.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-21557 Details

Status: Modified

Last updated: 🕠 21 Nov 2024, 05:48 UTC
Originally published on: 🕖 14 Jun 2021, 19:15 UTC

Time between publication and last update: 1255 days

CVSS Release: version 3

CVSS3 Source

security_alert@emc.com

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2021-21557 Vulnerability Summary

CVE-2021-21557: Dell PowerEdge Server BIOS and select Dell Precision Rack BIOS contain an out-of-bounds array access vulnerability. A local malicious user with high privileges may potentially exploit this vulnerability, leading to a denial of service, arbitrary code execution, or information disclosure in System Management Mode.

Assessing the Risk of CVE-2021-21557

Access Complexity Graph

The exploitability of CVE-2021-21557 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-2021-21557

The exploitability of CVE-2021-21557 is influenced by multiple factors. Security teams should analyze system configurations and apply appropriate countermeasures to mitigate threats.

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-2021-21557, 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-2021-21557, 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-2021-21557 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: High
    CVE-2021-21557 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: Low
    CVE-2021-21557 may slightly degrade system performance without fully affecting service availability.

Exploit Prediction Scoring System (EPSS)

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

EPSS Score: 0.089% (probability of exploit)

EPSS Percentile: 40.43% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 59.57% of others.

CVE-2021-21557 References

External References

CWE Common Weakness Enumeration

CWE-125

CAPEC Common Attack Pattern Enumeration and Classification

  • Overread Buffers CAPEC-540 An adversary attacks a target by providing input that causes an application to read beyond the boundary of a defined buffer. This typically occurs when a value influencing where to start or stop reading is set to reflect positions outside of the valid memory location of the buffer. This type of attack may result in exposure of sensitive information, a system crash, or arbitrary code execution.

Vulnerable Configurations

  • cpe:2.3:o:dell:poweredge_r640_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r640_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r640_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r640_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r640:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r640:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r740_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r740_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r740_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r740_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r740:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r740:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r740xd_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r740xd_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r740xd_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r740xd_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r740xd:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r740xd:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r940_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r940_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r940_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r940_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r940:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r940:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r540_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r540_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r540:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r540:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r440_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r440_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r440:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r440:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_t440_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_t440_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_t440:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_t440:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_xr2_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_xr2_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_xr2:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_xr2:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r740xd2_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r740xd2_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r740xd2:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r740xd2:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r840_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r840_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r840_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r840_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r840:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r840:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r940xa_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r940xa_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r940xa_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r940xa_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r940xa:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r940xa:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_t640_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_t640_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_t640:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_t640:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_c6420_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_c6420_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_c6420:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_c6420:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_fc640_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_fc640_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_fc640:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_fc640:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_m640_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_m640_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_m640:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_m640:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_m640p_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_m640p_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_m640p:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_m640p:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_mx740c_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_mx740c_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_mx740c_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_mx740c_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_mx740c:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_mx740c:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_mx840c_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_mx840c_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_mx840c_firmware:2.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_mx840c_firmware:2.9.4:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_mx840c:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_mx840c:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_c4140_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_c4140_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_c4140:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_c4140:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_t140_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_t140_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_t140:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_t140:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_t340_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_t340_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_t340:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_t340:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r240_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r240_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r240:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r240:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r340_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r340_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r340:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r340:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r6415_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r6415_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r6415:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r6415:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r7415_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r7415_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r7415:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r7415:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r7425_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r7425_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r7425:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r7425:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r6515_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r6515_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r6515:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r6515:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r7515_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r7515_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r7515:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r7515:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r6525_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r6525_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r6525:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r6525:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_r7525_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_r7525_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_r7525:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_r7525:-:*:*:*:*:*:*:*
  • cpe:2.3:o:dell:poweredge_c6525_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:dell:poweredge_c6525_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:h:dell:poweredge_c6525:-:*:*:*:*:*:*:*
    cpe:2.3:h:dell:poweredge_c6525:-:*:*:*:*:*:*:*

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