External risk intelligence

Veritas Backup Exec File Access Vulnerability.

CVE advisoryKnown Exploit

CVE-2021-27876

A vulnerability in Veritas Backup Exec Agent's authentication allows unauthorized access. An attacker can then access arbitrary files with system privileges, impacting data confidentiality and integrity. The business risk involves potential data exposure or manipulation.

2Halo Surface Signal

Veritas Backup Exec

before 21.2

External exposure likelihood

Halo Surface Signal score for CVE-2021-27876

This vulnerability affects a backup agent, which is typically deployed within internal network segments to facilitate communication between backup servers and protected endpoints. While network-reachable within an environment, these agents are rarely exposed directly to the public internet and are generally protected by internal network controls and firewall policies.

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in Veritas Backup Exec's authentication scheme allows an unauthorized attacker to gain access to the system. Once authenticated, the attacker can manipulate command parameters to access any file on the system with administrative privileges. This could lead to significant business risk through unauthorized data exposure or manipulation.

  • Vulnerable component: Veritas Backup Exec agent
  • Core weakness: Flawed authentication scheme
  • Main business impact: Unauthorized file access and data exposure

Attack Path

How an attacker could exploit the issue

An attacker can exploit a vulnerability in Veritas Backup Exec's authentication scheme to gain unauthorized access. This access allows the attacker to execute data management commands. By manipulating input parameters within these commands, the attacker can then access arbitrary files on the system with System privileges. This impacts system data integrity and confidentiality.

  • Unauthenticated access to the client.
  • Attacker executes data management commands.
  • Attacker accesses arbitrary files.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in Veritas Backup Exec could allow an unauthorized attacker to gain access to sensitive files on a system. The attack exploits a weakness in how client-to-agent communication is authenticated. Once authenticated, an attacker can manipulate commands to read arbitrary files with system-level privileges.

  • Attacker skill level: Low
  • Required access or conditions: Network access, authenticated user
  • Business risk or urgency: High, exploitation known

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Veritas Backup Exec Agent could allow an unauthorized attacker to gain elevated privileges and access arbitrary files on the system. Successful exploitation could lead to unauthorized data access and modification, impacting data integrity and confidentiality. Organizations should investigate their environment to identify all instances of the affected Veritas Backup Exec Agent.

  • Find affected Backup Exec Agent assets.
  • Reduce exposure by isolating affected systems.
  • Apply vendor updates and verify fixes.
  • Monitor for related security events.

Frequently asked questions

What is Veritas Backup Exec and its role in data protection?

Veritas Backup Exec is a software solution designed for backing up and restoring data. It plays a crucial role in helping organizations safeguard their valuable information by creating redundant copies. These backups are essential for recovering data in scenarios involving hardware failures, accidental deletions, or cyberattacks. The Backup Exec agent is a key component facilitating communication between the backup server and the systems being protected.

How does the CVE-2021-27876 vulnerability work?

This vulnerability stems from a flawed authentication mechanism in Veritas Backup Exec's agent communication. It allows an attacker to bypass normal authentication procedures. Once authenticated, the attacker can execute data management protocol commands. By manipulating these commands with crafted input, an attacker can access arbitrary files on the system with System privileges, compromising data integrity and confidentiality.

What is the weakness class exploited by CVE-2021-27876?

The primary weakness exploited by CVE-2021-27876 is CWE-287, which involves 'Improper Authentication'. This means the system does not correctly validate or verify the identity of a user or process, allowing an attacker to impersonate a legitimate entity or bypass authentication altogether. In this specific case, the flaw lies in the SHA Authentication scheme used for client-to-agent communication.

What is the relevance of CVE-2021-27876 to an organization?

This vulnerability presents a significant risk as it allows an unauthorized attacker to gain unauthorized file access with System privileges. The potential impact includes unauthorized data exposure, modification, or deletion, severely affecting data confidentiality and integrity. Given that the attack vector is network-based and requires only low privileges for an authenticated user, organizations must prioritize identifying and mitigating this risk to prevent potential data breaches or operational disruptions.

What steps should organizations take to respond to this threat?

Organizations should proactively identify all instances of the affected Veritas Backup Exec Agent within their environment. It is recommended to reduce the exposure of these systems by isolating them if possible. Applying vendor-provided updates to version 21.2 or later is crucial, and verifying that the fixes have been successfully implemented. Continuous monitoring for any related security events should also be part of the response strategy.

References