Skip to content

Security Sense

AI Threat Intelligence

  • About
  • Blog
  • Privacy Policy

Tag: command-injection

CVE-2026-110447: Collabora Online Built-in CODE Server OS Command Injection

Posted on November 3, 2026 by Kyle

Overview

CVE-2026-110447 is a critical OS command injection vulnerability affecting the Collabora Online Built-in CODE Server, specifically when deployed as a Nextcloud app. This flaw enables remote code execution, allowing attackers to execute arbitrary commands on the underlying system. It is currently being exploited in the wild, making immediate patching crucial for affected Nextcloud instances.

Technical Analysis

The vulnerability, CWE-78 (Improper Neutralization of Special Elements used in an OS Command), resides in the proxy.php component of the Collabora Online Built-in CODE Server (richdocumentscode) Nextcloud app.
* It affects versions prior to 26.4.303.
* Exploitation occurs when the CODE server is not actively running, such as immediately after a system restart or if the service has crashed.
* Attackers can inject arbitrary OS commands, leading to remote code execution (RCE) on the host system.
* This vulnerability specifically impacts Nextcloud deployments utilizing the Built-in CODE Server and does not affect standalone Collabora Online servers.
* Active exploitation has been observed in the wild, with XMRIG malware linked to post-exploitation activities.

Detection

  • Monitor web server access logs for requests to /index.php/apps/richdocumentscode/proxy.php containing suspicious command injection patterns (e.g., |, &, ;, $(...), ` followed by OS commands).
  • Look for unusual process spawns originating from the web server process (e.g., apache, nginx, php-fpm) that execute shell commands (sh, bash, cmd.exe, powershell.exe) or known malware binaries like XMRIG.
  • Monitor for unexpected outbound network connections from the web server to known C2 infrastructure or cryptocurrency mining pools.
  • Review system logs for errors related to the CODE server not running, which could indicate a vulnerable state.

Sigma Detection Rules

⚠️ AI-generated detection rules. These are experimental starting points. Review field names, EventIDs, and logic against your environment’s schema before deploying. Tune to reduce false positives.

Collabora Online CODE Server RCE Process Spawn

title: Collabora Online CODE Server RCE Process Spawn
id: c8f1e2d3-b4a5-6c7d-8e9f-0a1b2c3d4e5f
status: experimental
description: Detects suspicious process creation by web server processes, indicative of successful OS command injection in Collabora Online Built-in CODE Server (CVE-2026-110447).
logsource:
  product: linux
  service: auditd
detection:
  selection:
    ParentImage|endswith:
      - '/usr/sbin/apache2'
      - '/usr/sbin/httpd'
      - '/usr/bin/php-fpm'
      - '/usr/bin/nginx'
    Image|endswith:
      - '/bin/sh'
      - '/bin/bash'
      - '/usr/bin/wget'
      - '/usr/bin/curl'
      - '/usr/bin/python'
      - '/usr/bin/perl'
      - '/usr/local/bin/xmrig'
  condition: selection
level: critical

Collabora Online CODE Server Command Injection Attempt

title: Collabora Online CODE Server Command Injection Attempt
id: f0e1d2c3-a4b5-6d7e-8f9a-0b1c2d3e4f50
status: experimental
description: Detects patterns in web access logs indicative of OS command injection attempts against Collabora Online Built-in CODE Server (CVE-2026-110447).
logsource:
  category: webserver
  service: ['apache', 'nginx']
detection:
  selection:
    c-uri|contains:
      - '/index.php/apps/richdocumentscode/proxy.php'
      - '|'
      - '&'
      - ';'
      - '$('
      - '`'
      - 'cat /etc/passwd'
      - 'id'
      - 'whoami'
      - 'wget'
      - 'curl'
      - 'nc -e'
      - 'bash -i'
      - 'php -r'
  condition: selection
level: high

Mitigations

  1. Immediately update the Collabora Online Built-in CODE Server (richdocumentscode) Nextcloud app to version 26.4.303 or later.
  2. Ensure the CODE server service is configured for automatic restart and is actively running to reduce the window of vulnerability.
  3. Implement strict egress filtering to prevent unauthorized outbound connections from web servers, especially to cryptocurrency mining pools or unknown IP addresses.
  4. Apply the principle of least privilege to the web server user and associated processes to limit the impact of successful exploitation.
  5. Regularly back up critical data and test restoration procedures.

References

  • https://github.com/CollaboraOnline/richdocumentscode/issues/354
  • https://help.nextcloud.com/t/to-collabora-built-in-user-update-asap/250516
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-110447

Indicators of Compromise

Type Value Description
SHA256 19cd1fe4e501fbdf6e52a7249a7bd375ea3039feed596f56691fb7f353acc23f XMRIG · confidence 100% · first seen 2026-10-23
SHA256 2a6e2516b103c2f313d280e2e5954db9111515e401e603ebb6d4b47a65b086fb XMRIG · confidence 100% · first seen 2026-10-23
SHA256 4230d003e25b12be26130c9d941ef0b809dc7da2a25ecbf8d15a0c369730ebd0 XMRIG · confidence 100% · first seen 2026-10-23
SHA256 5220cce8158699825c206529746ad1cbb20d930eff244017f8c3f913b83a3d86 XMRIG · confidence 100% · first seen 2026-10-23
SHA256 9aade612521dab5600f59b0660e19fb8392a42570408673e824f3bbd2532c85b XMRIG · confidence 100% · first seen 2026-10-23
SHA256 c5bd9b66d5535c2dffa253cb6dd665d20208db58793fd176d4773093546f50df XMRIG · confidence 100% · first seen 2026-10-23
SHA256 e15d2363b9e4552250f230c62188cb299ff2570c9ba9589fbc3e190df84768ba XMRIG · confidence 100% · first seen 2026-10-23
IP Address 103.194.186.118 XMRIG · confidence 95% · first seen 2026-10-23
IP Address 212.83.185.19 XMRIG · confidence 95% · first seen 2026-10-23
URL http://212.83.185.19/bottom-xe.png XMRIG · confidence 100% · first seen 2026-10-23
URL http://212.83.185.19/footerd.png XMRIG · confidence 100% · first seen 2026-10-23
URL http://cqzbr8a4.requestrepo.com XMRIG · confidence 90% · first seen 2026-10-23

MITRE ATT&CK

  • T1190 — Exploit Public-Facing Application
  • T1059.004 — Unix Shell
  • T1496 — Resource Hijacking
🤖 AI Attribution
Generated by gemini-2.5-flash ·
2,000 input / 1,471 output tokens ·
Reviewed and approved by a human analyst before publication
Posted in vulnerabilityTagged collabora, command-injection, critical, linux, nextcloud, rce, vulnerability, webappLeave a comment

CVE-2026-105134: AhsayCBS Command Injection Vulnerability Actively Exploited

Posted on October 17, 2026 by Kyle

Overview

CVE-2026-105134 is a critical command injection vulnerability impacting Ahsay AhsayCBS backup software, specifically within its Replication Receiver component. This flaw enables unauthenticated remote attackers to execute arbitrary operating system commands by manipulating the random parameter in the /rps/api/json/UpdateReceivers.do endpoint. The vulnerability is actively exploited, with observed attacks deploying webshells and XMRig cryptominers.

Technical Analysis

This vulnerability exists in Ahsay AhsayCBS versions up to 10.3.2. The flaw is located in the /rps/api/json/UpdateReceivers.do endpoint of the Replication Receiver component. A remote attacker can achieve OS command injection by manipulating the random argument within requests to this endpoint. The vulnerability has a CVSS 3.1 score of 10.0 (CRITICAL) with vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H, indicating network-exploitable, low complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability.

  • Affected Component: Replication Receiver
  • Affected Endpoint: /rps/api/json/UpdateReceivers.do
  • Vulnerable Parameter: random
  • Affected Versions: Ahsay AhsayCBS up to 10.3.2
  • Attack Vector: Remote, unauthenticated command injection via HTTP/HTTPS requests.
  • Weaknesses: CWE-77 (Improper Neutralization of Special Elements used in a Command (‘Command Injection’)), CWE-78 (Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’))
  • Chaining: This vulnerability can be chained with CVE-2026-105133 for potentially broader impact.
  • Post-Exploitation: Observed post-exploitation activities include the deployment of webshells and XMRig cryptominers.

Detection

Defenders can identify exploitation attempts and post-exploitation activity through various log sources and behavioral indicators:

  • Web Server Logs: Monitor access logs for requests to /rps/api/json/UpdateReceivers.do where the random parameter in the query string or POST body contains suspicious characters indicative of command injection (e.g., &, |, ;, $(, `).
  • Process Creation Logs (Windows/Linux): Look for unusual child processes spawned by the AhsayCBS service process (e.g., AhsayCBS.exe, java.exe, or similar) that include cmd.exe, powershell.exe, sh, bash, python.exe, or other scripting interpreters.
  • File System Monitoring: Detect the creation of suspicious files in web root directories (e.g., .jsp, .php, .asp, .aspx files that are not part of the legitimate application) or the presence of known cryptominer executables like xmrig.exe.
  • Network Activity: Monitor for outbound connections from the AhsayCBS server to unusual IP addresses or domains, especially those associated with cryptomining pools or C2 infrastructure.
  • Resource Utilization: Look for sudden spikes in CPU usage on the AhsayCBS server, which could indicate cryptomining activity.

Sigma Detection Rules

⚠️ AI-generated detection rules. These are experimental starting points. Review field names, EventIDs, and logic against your environment’s schema before deploying. Tune to reduce false positives.

AhsayCBS CVE-2026-105134 Exploitation Attempt

title: AhsayCBS CVE-2026-105134 Exploitation Attempt
id: 7e2f1b3c-d4a5-4e6f-8b0c-9a1d2e3f4a5b
status: experimental
description: Detects attempts to exploit CVE-2026-105134 in AhsayCBS by looking for suspicious requests to the vulnerable endpoint with command injection patterns.
logsource:
  category: webserver
detection:
  selection_uri:
    cs-uri-stem|endswith: '/rps/api/json/UpdateReceivers.do'
  selection_injection_patterns:
    cs-uri-query|contains:
      - '&'
      - '|'
      - ';'
      - '`'
      - '$('
      - '||'
      - '&&'
  condition: selection_uri and selection_injection_patterns
level: high

AhsayCBS Service Spawning Suspicious Processes

title: AhsayCBS Service Spawning Suspicious Processes
id: 8c9d0e1f-a2b3-4c5d-6e7f-0a1b2c3d4e5f
status: experimental
description: Detects post-exploitation activity where the AhsayCBS service process spawns common command interpreters, indicative of command injection success.
logsource:
  product: windows
  service: sysmon
detection:
  selection_parent:
    ParentImage|endswith:
      - '\AhsayCBS.exe'
      - '\java.exe' # Common for Java-based services
  selection_child:
    Image|endswith:
      - '\cmd.exe'
      - '\powershell.exe'
      - '\sh.exe'
      - '\bash.exe'
      - '\python.exe'
  condition: selection_parent and selection_child
level: critical

XMRig Cryptominer Execution

title: XMRig Cryptominer Execution
id: 9d0e1f2a-b3c4-5d6e-7f8a-9b0c1d2e3f4a
status: experimental
description: Detects the execution of XMRig cryptominer, often deployed after successful exploitation of vulnerabilities like CVE-2026-105134.
logsource:
  product: windows
  service: sysmon
detection:
  selection:
    Image|endswith:
      - '\xmrig.exe'
      - '\xmrig-proxy.exe'
    CommandLine|contains:
      - '--donate-level'
      - '-o pool.supportxmr.com'
      - '-u wallet_address'
  condition: selection
level: high

Mitigations

  1. Patch Immediately: Upgrade Ahsay AhsayCBS to version 10.3.4 or later. This is the primary and most effective mitigation.
  2. Network Segmentation: Isolate AhsayCBS servers on a dedicated network segment with strict egress filtering to limit outbound connections and prevent lateral movement in case of compromise.
  3. Principle of Least Privilege: Ensure the AhsayCBS service runs with the minimum necessary privileges to perform its functions.
  4. Application Whitelisting: Implement application whitelisting to prevent the execution of unauthorized executables (e.g., xmrig.exe, unknown scripting interpreters) on the server.
  5. Regular Backups: Maintain regular, off-site, and immutable backups of critical data to facilitate recovery in the event of a successful attack.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-105134
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-105134
  • https://vuldb.com/cve/CVE-2026-105134
  • https://vuldb.com/submit/942743
  • https://vuldb.com/vuln/413351
  • https://vuldb.com/vuln/413351/cti
  • https://www.ahsay.com/en/support/help-centre/release-notes/cbs/v10.3.4
  • https://www.huntress.com/blog/ahsaycbs-flaws-exploit
  • https://ltna.com.au/cyber

Indicators of Compromise

Type Value Description
SHA256 05f69ae6b2b89c1c4dcf836bff032232f11bf0109f2b498e2345045d06139034 Modified NSSM utility (msedge.exe) (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)
SHA256 481728a7c9c4c02be07051d9c1958d902ea6397ebb8952ab83944818e3d25d21 Powershell script (Taskgmr.ps1) (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)
SHA256 4dcb0202fe8b2d4d7b183764e38184cd6ed50132786cc7e7d1f7f4bce1dd6f3d XMRig miner (edge.exe) (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)
IP Address 51.195.127.124 XMR cryptomining pool IP address (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)
Domain imagefiles-backup.oss-ap-southeast-7.aliyuncs.com Payload hosting domain (Alibaba Cloud Object Storage) (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)
Domain xmr.kryptex.network XMR cryptomining pool domain (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)
URL http://imagefiles-backup.oss-ap-southeast-7.aliyuncs.com Payload hosting server for various files (Taskgmr.ps1, msedge.exe, edge.exe, config.json, WinRing0x64.sys) (via https://www.huntress.com/blog/ahsaycbs-flaws-exploit)

MITRE ATT&CK

  • T1059 — Command and Scripting Interpreter
  • T1505.003 — Web Shell
  • T1496 — Resource Hijacking
  • T1036.005 — Match Legitimate Resource Name or Location
  • T1564 — Hide Artifacts
  • T1543.003 — Windows Service
  • T1608.001 — Upload Malware
  • T1190 — Exploit Public-Facing Application
  • T1036.004 — Masquerade Task or Service
  • T1057 — Process Discovery
  • T1059.001 — PowerShell
  • T1571 — Non-Standard Port
  • T1059.003 — Windows Command Shell
  • T1071.001 — Web Protocols
  • T1105 — Ingress Tool Transfer
  • T1569.002 — Service Execution
  • T1124 — System Time Discovery
🤖 AI Attribution
Generated by gemini-2.5-flash ·
2,137 input / 2,181 output tokens ·
Reviewed and approved by a human analyst before publication
Posted in vulnerabilityTagged ahsaycbs, command-injection, critical, cryptomining, known_cve, vulnerability, webshell, xmrigLeave a comment

CVE-2026-96951: Microsoft Windows Command Injection Vulnerability

Posted on October 17, 2026 by Kyle

Overview

CVE-2026-96951 is a high-severity command injection vulnerability affecting Microsoft Windows Shell. This flaw allows an unauthorized attacker to bypass security features over a network, with successful exploitation requiring user interaction. Its inclusion in CISA’s KEV catalog highlights its critical importance for immediate attention due to potential high impact on system confidentiality, integrity, and availability.

Technical Analysis

CVE-2026-96951 is an improper neutralization of special elements vulnerability (CWE-77) within Microsoft Windows Shell. This command injection flaw allows an unauthorized attacker to bypass security features. The attack vector is network-based (AV:N), and successful exploitation requires user interaction (UI:R) according to the CVSS 3.1 vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Specific affected Windows versions are not detailed in the provided information.

Detection

Detecting exploitation of CVE-2026-96951 involves monitoring for anomalous process execution and command line activity originating from Windows Shell components.

  • Monitor cmd.exe, powershell.exe, or other scripting interpreters being spawned as child processes of explorer.exe or other legitimate shell processes with unusual or encoded command-line arguments.
  • Look for command lines containing shell metacharacters (e.g., &, |, ;, &&, ||, (, )) that indicate an attempt to inject arbitrary commands.
  • Analyze process creation events (e.g., Sysmon Event ID 1) for processes launched with elevated privileges or from unexpected locations following shell interactions.
  • Review network logs for suspicious outbound connections initiated by shell processes that might indicate post-exploitation activity.

Sigma Detection Rules

⚠️ AI-generated detection rules. These are experimental starting points. Review field names, EventIDs, and logic against your environment’s schema before deploying. Tune to reduce false positives.

Suspicious Interpreter Spawn from Explorer

title: Suspicious Interpreter Spawn from Explorer
id: 2b1a2c3d-4e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects suspicious command interpreter processes spawned directly by explorer.exe, which could indicate command injection exploitation.
logsource:
  product: windows
  service: sysmon
detection:
  selection:
    ParentImage|endswith: '\explorer.exe'
    Image|endswith:
      - '\cmd.exe'
      - '\powershell.exe'
      - '\pwsh.exe'
      - '\wscript.exe'
      - '\cscript.exe'
  condition: selection
level: high

Command Line Injection Metacharacters

title: Command Line Injection Metacharacters
id: 3c4d5e6f-7a8b-9c0d-1e2f-3a4b5c6d7e8f
status: experimental
description: Detects command lines containing common shell metacharacters often used in command injection attacks. This rule may be noisy and require tuning.
logsource:
  product: windows
  service: sysmon
detection:
  selection:
    EventID: 1
    Image|endswith:
      - '\cmd.exe'
      - '\powershell.exe'
      - '\pwsh.exe'
    CommandLine|contains:
      - ' & '
      - ' | '
      - ' ; '
      - ' && '
      - ' || '
      - '`' # Backtick for PowerShell
      - '$( ' # PowerShell subexpression
      - '`n' # Newline for PowerShell
  condition: selection
level: medium

Mitigations

  1. Apply the security update for CVE-2026-96951 from Microsoft as soon as it becomes available.
  2. Implement principle of least privilege for users and services to limit the impact of successful exploitation.
  3. Restrict network access to systems running Windows Shell components from untrusted networks where possible.
  4. Educate users on identifying and avoiding suspicious links or files, especially if user interaction is a prerequisite for exploitation.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-96951
  • https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96951
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-96951

Indicators of Compromise

No public IOCs available at time of writing.

MITRE ATT&CK

  • T1059.003 — Windows Command Shell
🤖 AI Attribution
Generated by gemini-2.5-flash ·
1,688 input / 1,282 output tokens ·
Reviewed and approved by a human analyst before publication
Posted in vulnerabilityTagged command-injection, cve, high, vulnerability, windowsLeave a comment

CVE-2026-73570: Unauthenticated Command Injection in Zimbra

Posted on October 1, 2026 by Kyle

Overview

CVE-2026-73570 describes an unauthenticated command injection vulnerability impacting Zimbra mail servers. This flaw allows remote attackers to execute arbitrary commands on vulnerable internet-facing systems without prior authentication, posing a severe risk to email infrastructure and sensitive data.

Technical Analysis

This vulnerability is an unauthenticated command injection affecting Zimbra mail servers. While specific details regarding the vulnerable component or the exact injection vector are not publicly detailed in the provided source, successful exploitation enables an attacker to execute arbitrary operating system commands on the underlying server. Given the nature of command injection, this typically involves manipulating input fields or parameters that are processed by the server-side application without proper sanitization, leading to the execution of attacker-controlled commands within the context of the vulnerable service.

Detection

  • Monitor Zimbra server logs for unusual process creation events, especially shell interpreters (sh, bash, python, perl) spawned by web server processes (e.g., httpd, nginx, java, tomcat, jetty).
  • Look for unexpected outbound network connections originating from Zimbra processes to unusual or external IP addresses.
  • Review web server access logs for suspicious requests containing command injection payloads (e.g., $(command), && command, | command).
  • Monitor for modifications to critical Zimbra configuration files or the creation of new, unauthorized files in web-accessible directories.

Sigma Detection Rules

⚠️ AI-generated detection rules. These are experimental starting points. Review field names, EventIDs, and logic against your environment’s schema before deploying. Tune to reduce false positives.

Zimbra Command Injection – Suspicious Shell Process Creation

title: Zimbra Command Injection - Suspicious Shell Process Creation
id: 00000000-0000-0000-0000-000000000001
status: experimental
description: Detects suspicious shell process creation (sh, bash) by common web server processes on Linux, indicative of command injection exploitation on a Zimbra server.
logsource:
  product: linux
  service: process_creation
detection:
  selection_parent:
    ParentImage|contains:
      - 'httpd'
      - 'nginx'
      - 'java'
      - 'tomcat'
      - 'jetty'
      - 'zimbra'
  selection_child:
    Image|endswith:
      - '/bin/sh'
      - '/bin/bash'
      - '/usr/bin/sh'
      - '/usr/bin/bash'
  condition: all of selection_*
level: critical

Mitigations

  1. Patch Immediately: Apply the latest security updates and patches provided by Zimbra to address CVE-2026-73570. Refer to official Zimbra security advisories for specific version requirements.
  2. Network Segmentation: Isolate Zimbra mail servers within a dedicated network segment, limiting their ability to initiate connections to internal systems and restricting inbound access to only necessary ports and trusted sources.
  3. Implement Web Application Firewall (WAF): Deploy a WAF in front of Zimbra servers to detect and block common web-based attack patterns, including command injection attempts.
  4. Least Privilege: Ensure Zimbra services run with the minimum necessary privileges to reduce the impact of successful exploitation.
  5. Enhanced Logging and Monitoring: Enable comprehensive logging for process creation, network connections, and web access on Zimbra servers, and integrate these logs with a SIEM for real-time analysis and alerting.

References

  • https://www.microsoft.com/en-us/security/blog/2026/09/30/unauthenticated-command-injection-on-internet-facing-mail-servers-tracking-cve-2026-73570/

Indicators of Compromise

No public IOCs available at time of writing.

MITRE ATT&CK

  • T1213.001 — Confluence
  • T1059.004 — Unix Shell
🤖 AI Attribution
Generated by gemini-2.5-flash ·
1,645 input / 1,022 output tokens ·
Reviewed and approved by a human analyst before publication
Posted in vulnerabilityTagged command-injection, critical, mail-server, vulnerability, zimbraLeave a comment

CVE-2026-39808: Fortinet FortiSandbox OS Command Injection Vulnerability

Posted on July 23, 2026 - September 27, 2026 by Kyle

Overview

CVE-2026-39808 is a critical OS command injection vulnerability affecting Fortinet FortiSandbox appliances. An unauthenticated attacker can exploit this flaw by sending specially crafted HTTP requests, leading to arbitrary code or command execution on the device. Given its presence in CISA’s KEV catalog and community intelligence, this vulnerability is actively exploited and poses an immediate threat to unpatched systems.

Technical Analysis

This vulnerability, classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), allows for OS command injection. An unauthenticated attacker can leverage crafted HTTP requests to inject and execute unauthorized commands within the underlying operating system of the FortiSandbox appliance.

  • Affected Products: Fortinet FortiSandbox versions 4.4.0 through 4.4.9.
  • Attack Vector: Network (AV:N). Exploitation is possible remotely without authentication (PR:N) and requires no user interaction (UI:N).
  • Impact: Successful exploitation grants an attacker high confidentiality, integrity, and availability impact (C:H/I:H/A:H) by allowing arbitrary code or command execution.
  • CVSS 3.1 Score: 9.8 (CRITICAL) – CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Detection

Defenders should focus on monitoring web server logs for suspicious request patterns and host-based logs for unusual process execution on FortiSandbox appliances.

  • Web Server Logs: Monitor FortiSandbox web access logs for HTTP requests containing common command injection payloads (e.g., |, &, ;, $(...), `...`) followed by system commands like id, whoami, cat /etc/passwd, or uname -a within the URI path (cs-uri-stem) or query parameters (cs-uri-query).
  • Process Monitoring: Look for unexpected process spawns on the FortiSandbox appliance, particularly shell processes (sh, bash, python) originating from the web server process or other services exposed to the network.
  • Network IDS/IPS: Deploy and update network intrusion detection/prevention systems with signatures capable of identifying known exploit patterns for CVE-2026-39808.
  • Outbound Connections: Monitor FortiSandbox for unusual outbound network connections to external IP addresses or non-standard ports, which could indicate a successful reverse shell or data exfiltration.

Sigma Detection Rules

⚠️ AI-generated detection rules. These are experimental starting points. Review field names, EventIDs, and logic against your environment’s schema before deploying. Tune to reduce false positives.

Fortinet FortiSandbox OS Command Injection Attempt (CVE-2026-39808)

title: Fortinet FortiSandbox OS Command Injection Attempt (CVE-2026-39808)
id: d7f1e2c3-a4b5-4c6d-8e9f-0123456789ab
status: experimental
description: Detects potential OS command injection attempts targeting Fortinet FortiSandbox via crafted HTTP requests containing shell metacharacters and commands.
logsource:
  category: webserver
detection:
  selection:
    - cs-uri-stem|contains:
        - '|id'
        - '&whoami'
        - ';cat /etc/passwd'
        - '$(uname -a)'
        - '`ls -la`'
    - cs-uri-query|contains:
        - '|id'
        - '&whoami'
        - ';cat /etc/passwd'
        - '$(uname -a)'
        - '`ls -la`'
  condition: selection
level: critical

Fortinet FortiSandbox Suspicious Shell Process Spawn (CVE-2026-39808 Post-Exploitation)

title: Fortinet FortiSandbox Suspicious Shell Process Spawn (CVE-2026-39808 Post-Exploitation)
id: e8d2f3c4-b5a6-4d7e-9f01-23456789abcd
status: experimental
description: Detects suspicious shell process spawns on FortiSandbox, potentially indicating successful OS command injection. Assumes Linux-based OS.
logsource:
  product: linux
  service: auditd # Or other process logging source like Sysmon for Linux
detection:
  selection:
    - a0|contains:
        - '/bin/sh'
        - '/bin/bash'
        - '/usr/bin/python'
        - '/usr/bin/perl'
    - ppid_name|contains:
        - 'httpd'
        - 'nginx'
        - 'fortiwebd' # Placeholder for a potential Fortinet web server process name
        - 'uwsgi'
  condition: selection
level: critical

Mitigations

Prioritize patching and network segmentation to reduce exposure.

  1. Patch Immediately: Upgrade Fortinet FortiSandbox appliances to a version beyond 4.4.9 as soon as a patched release is available from Fortinet. Refer to the vendor advisory for specific patch details.
  2. Restrict Network Access: Limit network access to the FortiSandbox management interface and any exposed web services to only trusted administrative networks and necessary internal systems. Implement strict firewall rules.
  3. Implement Web Application Firewall (WAF): Deploy a WAF in front of the FortiSandbox to filter and block malicious HTTP requests attempting to exploit command injection vulnerabilities.
  4. Regular Auditing: Conduct regular security audits and vulnerability scans of FortiSandbox appliances to identify and remediate potential weaknesses.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-39808
  • https://fortiguard.fortinet.com/psirt/FG-IR-26-100
  • https://github.com/samu-delucas/CVE-2026-39808
  • https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-39808
  • https://kudelskisecurity.com/research/fortinet-fortibleed-global-compromise-active-exploitation-of-fortinet-vulnerabilities

Indicators of Compromise

No public IOCs available at time of writing.

MITRE ATT&CK

  • T1190 — Exploit Public-Facing Application
  • T1059.004 — Unix Shell
  • T1040 — Network Sniffing
  • T1078 — Valid Accounts
  • T1110 — Brute Force
  • T1110.002 — Password Cracking
  • T1110.004 — Credential Stuffing
  • T1133 — External Remote Services
  • T1595 — Active Scanning
🤖 AI Attribution
Generated by gemini-2.5-flash ·
2,081 input / 1,754 output tokens ·
Reviewed and approved by a human analyst before publication
Posted in vulnerabilityTagged command-injection, critical, cve, fortinet, fortisandbox, kev, vulnerabilityLeave a comment
Proudly powered by WordPress | Theme: micro, developed by DevriX.