CVE-2021-27876

Veritas Backup Exec Agent: File Access

As of , CVE-2021-27876 in Veritas Backup Exec Agent is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 7 April 2023
US federal deadline
28 April 202321 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Known
EPSS score
0.14Higher than 96% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
0.00 on 7 April 2023EPSS on the day CISA listed it.
Public exploit
1 Metasploit module
Fix
Vendor advice: www.veritas.comLinks below, from CISA's entry.

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

Veritas Backup Exec (BE) Agent contains a file access vulnerability that could allow an attacker to specially craft input parameters on a data management protocol command to access files on the BE Agent machine.

CISA's description

An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which is typically completed over a secure TLS communication. However, due to a vulnerability in the SHA Authentication scheme, an attacker is able to gain unauthorized access and complete the authentication process. Subsequently, the client can execute data management protocol commands on the authenticated connection. By using crafted input parameters in one of these commands, an attacker can access an arbitrary file on the system using System privileges.

The CVE record's description, from mitre

CVE published
1 March 2021
Assigned by
mitre
CVSS
8.1 High (CVSS 3.1, from the CNA)
CWE-287
Improper Authentication
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Public exploits

Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.

  • Metasploit: Veritas Backup Exec Agent Remote Code Executionexploit module, rank excellent

Backup Exec Agent: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2021-27877Improper AuthenticationVeritas Backup Exec AgentPatch this weekRansomware use; Metasploit module; EPSS 0.650.65
CVE-2021-27878Command ExecutionVeritas Backup Exec AgentPatch this weekRansomware use; Metasploit module0.24

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