Barracuda Networks ESG Appliance Improper Input Validation
CVE-2023-2868 is a critical-severity improper neutralization of special elements used in a command vulnerability in Barracuda Email Security Gateway from Barracuda, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 9.2.0.006 as the first without the flaw, so updating Barracuda Email Security Gateway to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on May 26, 2023, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Barracuda Email Security Gateway to 9.2.0.006 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on status.barracuda.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Barracuda | Barracuda Email Security Gateway | 5.1.3.001 up to, but not including, 9.2.0.006 | 9.2.0.006 |
| Barracuda | Email Security Gateway 300 Firmware | 5.1.3.001 through 9.2.0.006 | Not stated |
| Barracuda | Email Security Gateway 400 Firmware | 5.1.3.001 through 9.2.0.006 | Not stated |
| Barracuda | Email Security Gateway 600 Firmware | 5.1.3.001 through 9.2.0.006 | Not stated |
| Barracuda | Email Security Gateway 800 Firmware | 5.1.3.001 through 9.2.0.006 | Not stated |
| Barracuda | Email Security Gateway 900 Firmware | 5.1.3.001 through 9.2.0.006 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.4 | Critical | CNA (google.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
A remote command injection vulnerability exists in the Barracuda Email Security Gateway (appliance form factor only) product effecting versions 5.1.3.001-9.2.0.006. The vulnerability arises out of a failure to comprehensively sanitize the processing of .tar file (tape archives). The vulnerability stems from incomplete input validation of a user-supplied .tar file as it pertains to the names of the files contained within the archive. As a consequence, a remote attacker can specifically format these file names in a particular manner that will result in remotely executing a system command through Perl's qx operator with the privileges of the Email Security Gateway product. This issue was fixed as part of BNSF-36456 patch. This patch was automatically applied to all customer appliances.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in a Command
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- If possible, ensure that all external commands called from the program are statically created.
- Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
More Improper Neutralization of Special Elements used in a Command vulnerabilities (CWE-77)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-2868US Government Resource
Recent Improper Neutralization of Special Elements used in a Command vulnerabilities
- 7.2 High severity
- 8.8 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
- 9.8 Critical severity
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