Barracuda Networks ESG Appliance Improper Input Validation Vulnerability
Barracuda Networks · Email Security Gateway (ESG) Appliance
The Barracuda Email Security Gateway (ESG) Appliance contains an improper input validation flaw in its handling of .tar archives, where file names inside a supplied archive are not fully sanitized. An unauthenticated remote attacker with network access can craft a .tar file with specially formatted file names that causes a system command to be executed through Perl's qx operator, requiring no user interaction and running with the privileges of the Email Security Gateway product.
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.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 4/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.How attackers get in
What they do
What can follow
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 6 days before it was disclosed. Public exploit code (Metasploit) was available 1 day before disclosure.
- First seen exploitedVulnCheck KEV evidence6 days before
- Public exploit codeMetasploit1 day before
- Disclosedday 0
- Added to CISA KEVEU database agrees+2 days
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
4 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 4Initial AccessTA0001
CVE-2023-2868 in the Barracuda Email Security Gateway (ESG) had been reportedly exploited for espionage and exfiltration efforts by UNC4841 attributed by Mandiant. Following the exploitation of CVE-2023-2868, malware SALTWATER, SEASPY, and SEASIDE were identified to be used in intrusions.
ExecutionTA0002
Command and ControlTA0011
ExfiltrationTA0010
Detection
0 rules for this CVE · 211 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2023-2868 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Spearphishing AttachmentT1566.00124 general rules
- Droppers Exploiting CVE-2017-11882criticalstable
- Ursnif Malware C2 URL Patterncriticalstable
- Exploit for CVE-2017-8759criticaltest
- Suspicious Double Extension File Executionhighstable
- HTML Help HH.EXE Suspicious Child Processhightest
- ISO File Created Within Temp Foldershightest
- Office Macro File Creation From Suspicious Processhightest
- Password Protected ZIP File Opened (Email Attachment)hightest
Command and Scripting InterpreterT105995 general rules
- HackTool - Sliver C2 Implant Activity Patterncriticaltest
- Lazarus Group Activitycriticaltest
- REvil Kaseya Incident Malware Patternscriticaltest
- Turla Group Lateral Movementcriticaltest
- Windows Defender AMSI Trigger Detectedhighstable
- Windows Defender Threat Detectedhighstable
- Abusable DLL Potential Sideloading From Suspicious Locationhightest
- Add Insecure Download Source To Wingethightest
Ingress Tool TransferT110587 general rules
- Greenbug Espionage Group Indicatorscriticaltest
- Pandemic Registry Keycriticaltest
- Curl Download And Execute Combinationhightest
- File Download And Execution Via IEExec.EXEhightest
- File Download From IP Based URL Via CertOC.EXEhightest
- File Download Using Notepad++ GUP Utilityhightest
- File Download Via Bitsadmin To A Suspicious Target Folderhightest
- File Download Via Windows Defender MpCmpRun.EXEhightest
Exfiltration Over C2 ChannelT10415 general rules
- Equation Group C2 Communicationhightest
- OpenCanary - TFTP Requesthightest
- Shai-Hulud NPM Package Malicious Exfiltration via Curlhighexperimental
- Network Communication Initiated To Portmap.IO Domainmediumtest
- Tunneling Tool Executionmediumtest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX