Executive Summary
CVE-2026-17561 is a critical code injection vulnerability in Logsign SIEM, developed by Innotim Software, Telecommunications and Consulting Trade Ltd. Co. The flaw allows an attacker to inject and execute arbitrary code, achieving remote code execution on systems running Logsign SIEM versions prior to 6.4.108.
CVSS Score: 9.8 (Critical)
Organizations running Logsign SIEM should treat this as an emergency patch priority given the severity and the strategic value of SIEM platforms as targets — attackers who compromise a SIEM gain visibility into an organization's entire security event stream.
Vulnerability Overview
CWE Classification
- CWE-94: Improper Control of Generation of Code ("Code Injection")
Code injection flaws occur when user-supplied input is incorporated into dynamically generated code without sufficient sanitization or escaping. In the context of a SIEM platform, this attack surface is particularly dangerous: log ingestion pipelines, search query parsers, alert rule evaluators, and dashboard renderers all process external or semi-trusted data.
Attack Vector
| Attribute | Value |
|---|---|
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Changed |
| CVSS v3.1 Score | 9.8 Critical |
The combination of network-accessible, unauthenticated, and no user interaction required makes this vulnerability particularly dangerous for internet-facing Logsign deployments.
Technical Details
What Is Logsign SIEM?
Logsign SIEM is a Security Information and Event Management platform used by enterprises and managed security service providers (MSSPs) to collect, normalize, correlate, and alert on security events. It ingests logs from firewalls, endpoints, cloud services, and network devices, making it a high-value target: compromise of the SIEM gives an attacker visibility into an organization's full security monitoring capability.
Code Injection in SIEM Context
Common injection points in SIEM platforms include:
1. Log parsing and normalization pipelines
2. Search and query interfaces (custom query languages)
3. Alert correlation rule engines
4. Dashboard and report generation
5. Integration connectors and API handlersA code injection flaw in any of these paths — particularly one that evaluates user-supplied expressions — can allow an attacker to break out of the intended execution context and run arbitrary OS commands.
Exploitation Scenario
1. Attacker identifies Logsign SIEM instance (internet-facing or reachable via pivot)
2. Sends crafted HTTP request containing malicious code payload to vulnerable endpoint
3. Logsign processes the payload within a code evaluation context
4. Injected code executes with SIEM service privileges
5. Attacker achieves RCE: deploy backdoor, exfiltrate credentials/logs, pivot to internal networkBecause SIEM systems typically run with elevated privileges and have broad network access (to receive logs from all monitored systems), post-exploitation from this foothold is highly impactful.
Risk Assessment
Why SIEM Compromise Is Especially Dangerous
| Risk | Detail |
|---|---|
| Credential exposure | SIEM aggregates authentication logs — plaintext or hashed credentials often pass through |
| Blind-spot creation | Attacker can suppress, alter, or delete alerts and log entries |
| Network pivoting | SIEM has access to log sources across the environment — firewalls, AD, endpoints |
| Intelligence gathering | Full visibility into the organization's security monitoring rules and gaps |
| Supply-chain risk | MSSPs running Logsign for multiple clients: one compromise = multiple victims |
Remediation
Immediate Action: Patch to 6.4.108 or Later
Update Logsign SIEM to version 6.4.108 or newer as the primary remediation.
# Verify current Logsign version
# Check Logsign admin panel: Settings > System > Version Info
# Apply the update via Logsign's update mechanism
# Consult your Logsign vendor support portal for update packagesNetwork-Level Mitigations (Compensating Controls)
If patching is not immediately possible:
# 1. Restrict Logsign SIEM to management network only
# Block internet access to the SIEM web interface
# Example iptables rule (adjust interface/port as needed)
iptables -I INPUT -p tcp --dport 443 -s <trusted_mgmt_cidr> -j ACCEPT
iptables -I INPUT -p tcp --dport 443 -j DROP
# 2. Deploy WAF in front of Logsign to filter malicious payloads
# Block code injection patterns in HTTP request bodies and parameters
# 3. Monitor Logsign process for anomalous child process spawningDetection
Look for unusual process activity spawned by the Logsign service process:
# Splunk — detect anomalous child processes from SIEM service
index=endpoint sourcetype=sysmon EventCode=1
| where ParentImage LIKE "*logsign*"
| where NOT (Image IN ("expected_child_processes"))
| table _time, ParentImage, Image, CommandLine, User# Sigma rule — code injection child process from SIEM
title: Logsign SIEM Suspicious Child Process
status: experimental
logsource:
category: process_creation
product: linux
detection:
selection:
ParentCommandLine|contains: 'logsign'
filter_legit:
Image|endswith:
- '/java'
- '/sh'
condition: selection and not filter_legit
falsepositives:
- Legitimate administrative scripts
level: high