CVE-2021-1375 Vulnerability Analysis & Exploit Details

CVE-2021-1375
Vulnerability Scoring

6.7
/10
High Risk

If left unpatched, CVE-2021-1375 could lead to major system disruptions or data loss.

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: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-1375 Details

Status: Modified

Last updated: 🕠 21 Nov 2024, 05:44 UTC
Originally published on: 🕘 24 Mar 2021, 21:15 UTC

Time between publication and last update: 1337 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

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

CVE-2021-1375 Vulnerability Summary

CVE-2021-1375: Multiple vulnerabilities in the fast reload feature of Cisco IOS XE Software running on Cisco Catalyst 3850, Cisco Catalyst 9300, and Cisco Catalyst 9300L Series Switches could allow an authenticated, local attacker to either execute arbitrary code on the underlying operating system, install and boot a malicious software image, or execute unsigned binaries on an affected device. These vulnerabilities are due to improper checks performed by system boot routines. To exploit these vulnerabilities, the attacker would need privileged access to the CLI of the device. A successful exploit could allow the attacker to either execute arbitrary code on the underlying operating system or execute unsigned code and bypass the image verification check part of the secure boot process. For more information about these vulnerabilities, see the Details section of this advisory.

Assessing the Risk of CVE-2021-1375

Access Complexity Graph

The exploitability of CVE-2021-1375 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-2021-1375

The exploitability of CVE-2021-1375 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-2021-1375, 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-2021-1375, 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-2021-1375 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: High
    CVE-2021-1375 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: High
    CVE-2021-1375 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: 0.042% (probability of exploit)

EPSS Percentile: 5.07% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 94.93% of others.

CVE-2021-1375 References

External References

CWE Common Weakness Enumeration

CWE-347

CAPEC Common Attack Pattern Enumeration and Classification

  • Padding Oracle Crypto Attack CAPEC-463 An adversary is able to efficiently decrypt data without knowing the decryption key if a target system leaks data on whether or not a padding error happened while decrypting the ciphertext. A target system that leaks this type of information becomes the padding oracle and an adversary is able to make use of that oracle to efficiently decrypt data without knowing the decryption key by issuing on average 128*b calls to the padding oracle (where b is the number of bytes in the ciphertext block). In addition to performing decryption, an adversary is also able to produce valid ciphertexts (i.e., perform encryption) by using the padding oracle, all without knowing the encryption key.
  • Signature Spoofing by Improper Validation CAPEC-475 An adversary exploits a cryptographic weakness in the signature verification algorithm implementation to generate a valid signature without knowing the key.

Vulnerable Configurations

  • cpe:2.3:o:cisco:ios_xe:16.5.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.5.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.5.1a:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.5.1a:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.3:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.4:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.4:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.4a:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.4a:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.4s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.4s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.5:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.5:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.6:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.6:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.6.7:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.6.7:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.8.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.8.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.8.1a:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.8.1a:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.8.1s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.8.1s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.1s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.1s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.2s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.2s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.3:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.3:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.3a:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.3a:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.3s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.3s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.9.4:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.9.4:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.10.1e:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.10.1e:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.10.1s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.10.1s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.11.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.11.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.11.1b:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.11.1b:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.11.1c:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.11.1c:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.11.1s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.11.1s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.11.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.11.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.12.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.12.1:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.12.1c:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.12.1c:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.12.1s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.12.1s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.12.2:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.12.2:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.12.2s:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.12.2s:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:16.12.2t:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:16.12.2t:*:*:*:*:*:*:*
  • cpe:2.3:o:cisco:ios_xe:17.1.1:*:*:*:*:*:*:*
    cpe:2.3:o:cisco:ios_xe:17.1.1:*:*:*:*:*:*:*

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