CVE-2020-27736 Vulnerability Analysis & Exploit Details

CVE-2020-27736
Vulnerability Scoring

6.5
/10
High Risk

If left unpatched, CVE-2020-27736 could lead to major system disruptions or data loss.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and 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-2020-27736 Details

Status: Modified

Last updated: 🕙 08 Aug 2023, 10:15 UTC
Originally published on: 🕘 22 Apr 2021, 21:15 UTC

Time between publication and last update: 837 days

CVSS Release: version 3

CVSS3 Source

nvd@nist.gov

CVSS3 Type

Primary

CVSS3 Vector

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

CVE-2020-27736 Vulnerability Summary

CVE-2020-27736: A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2017.02.3), Nucleus ReadyStart V4 (All versions < V4.1.0), Nucleus Source Code (Versions including affected DNS modules), SIMOTICS CONNECT 400 (All versions < V0.5.0.0), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS domain name label parsing functionality does not properly validate the null-terminated name in DNS-responses. The parsing of malformed responses could result in a read past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to cause a denial-of-service condition or leak the read memory.

Assessing the Risk of CVE-2020-27736

Access Complexity Graph

The exploitability of CVE-2020-27736 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-2020-27736

CVE-2020-27736 presents a challenge to exploit due to its high attack complexity, but the absence of privilege requirements still makes it a viable target for skilled attackers. A thorough security review is advised.

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-2020-27736, 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-2020-27736, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: Low
    CVE-2020-27736 could lead to minor leaks of non-critical information without major privacy breaches.
  • Integrity: None
    CVE-2020-27736 poses no threat to data integrity.
  • Availability: High
    CVE-2020-27736 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: 0.223% (probability of exploit)

EPSS Percentile: 61.07% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 38.93% of others.

CVE-2020-27736 References

External References

CWE Common Weakness Enumeration

CWE-170

Vulnerable Configurations

  • cpe:2.3:a:siemens:nucleus_net:*:*:*:*:*:*:*:*
    cpe:2.3:a:siemens:nucleus_net:*:*:*:*:*:*:*:*
  • cpe:2.3:a:siemens:nucleus_readystart_v3:2013.08:*:*:*:*:*:*:*
    cpe:2.3:a:siemens:nucleus_readystart_v3:2013.08:*:*:*:*:*:*:*
  • cpe:2.3:a:siemens:nucleus_source_code:-:*:*:*:*:*:*:*
    cpe:2.3:a:siemens:nucleus_source_code:-:*:*:*:*:*:*:*
  • cpe:2.3:o:siemens:simotics_connect_400_firmware:-:*:*:*:*:*:*:*
    cpe:2.3:o:siemens:simotics_connect_400_firmware:-:*:*:*:*:*:*:*
  • cpe:2.3:o:siemens:simotics_connect_400_firmware:0.3.0.95:*:*:*:*:*:*:*
    cpe:2.3:o:siemens:simotics_connect_400_firmware:0.3.0.95:*:*:*:*:*:*:*
  • cpe:2.3:h:siemens:simotics_connect_400:-:*:*:*:*:*:*:*
    cpe:2.3:h:siemens:simotics_connect_400:-:*:*:*:*:*:*:*

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