CVE-2026-76461 IBM QRadar · QRadar

Detect Cisco Secure Email Gateway SQL Injection (CVE-2026-76461) in IBM QRadar

Detects exploitation attempts against CVE-2026-76461, a SQL injection vulnerability (CWE-89) in Cisco Secure Email Gateway (ESA). An unauthenticated or authenticated attacker can inject crafted SQL into web management or API request parameters, enabling data exfiltration, authentication bypass, or manipulation of the underlying database. This CVE is listed in the CISA KEV catalog (BOD 26-04). Detection focuses on SQL injection signatures in HTTP requests to the ESA management interface and API endpoints, anomalous database errors, and suspicious query patterns in web and syslog telemetry.

MITRE ATT&CK

Tactic
Initial Access Collection

QRadar Detection Query

IBM QRadar (QRadar)
sql 
SELECT sourceip, destinationip, "URL", "Request Method", QIDNAME(qid) AS event_name, COUNT(*) AS attempts, MIN(starttime) AS first_seen, MAX(starttime) AS last_seen FROM events WHERE (LOGSOURCETYPENAME(devicetype) ILIKE '%Cisco%' OR "DeviceProduct" ILIKE '%Email Security%' OR "DeviceProduct" ILIKE '%IronPort%') AND (LOWER("URL") IMATCHES '.*(union\s+select|information_schema|.--|sleep\(|waitfor\s+delay|extractvalue\(|updatexml\(|xp_cmdshell).*' OR LOWER(payload) IMATCHES '.*(union\s+select|information_schema|xp_cmdshell).*') GROUP BY sourceip, destinationip, event_name ORDER BY attempts DESC LAST 24 HOURS
high severity medium confidence

AQL query flagging SQL injection payload patterns in Cisco ESA web/API events within QRadar.

Data Sources

Cisco ESA syslogQRadar flow/event data

Required Tables

events

False Positives & Tuning

  • Sanctioned vulnerability scans against the mail gateway
  • Penetration testing
  • Benign administrative searches containing SQL keywords

Other platforms for CVE-2026-76461

Microsoft Sentinel (KQL) Splunk (SPL) Elastic Security (Elastic) Sumo Logic CSE (Sumo) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

Testing Methodology

Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.

  1. Test 1Error-based SQL injection probe against ESA login endpoint

    Expected signal: ESA web/API access log entry containing the single-quote/OR payload in the username parameter; WAF/IPS SQLi signature hit.

  2. Test 2UNION-based SQL injection against ESA API

    Expected signal: HTTP request log with 'UNION SELECT' in the URL query string against an /api/ endpoint on the ESA appliance.

  3. Test 3Time-based blind SQL injection against ESA

    Expected signal: ESA web log entry containing 'SLEEP(' time-delay payload; server response latency of ~5s recorded in proxy logs.

Last updated: 2026-09-15 Research depth: standard
References (4)

Response Playbook

Triage

  1. Confirm the source IP and whether it is internal, a known scanner, or an external/untrusted address; check reputation of external sources.
  2. Extract the full request URL, method, and body from the matched ESA log entry and identify the exact injected SQL payload and targeted endpoint (e.g., /api/, /login, /csa).
  3. Determine the affected Cisco Secure Email Gateway appliance and check its running AsyncOS version against the fixed release in Cisco advisory cisco-sa-esa-inj-2bLVGmhX.
  4. Review whether the injection attempt returned HTTP 200 with anomalous response size or database error strings, indicating a successful injection versus a blocked/failed attempt.

Containment

  1. Apply the Cisco patch for CVE-2026-76461 (upgrade AsyncOS per advisory) or, if immediate patching is not possible, restrict management/API interface access to a trusted admin network via ACLs.
  2. Block the offending source IP at the perimeter firewall or WAF and add SQLi payload signatures to the inline WAF/IPS protecting the appliance.
  3. If successful exploitation is confirmed, isolate the appliance from untrusted networks and rotate any credentials or API tokens stored on or accessible from the ESA.

Evidence Collection

  1. Capture and preserve ESA web/API access logs, authentication logs, and syslog covering the attack window, plus any database or GUI error logs.
  2. Export the full raw matched events (request/response pairs) and take a configuration snapshot / support bundle from the appliance for forensic analysis.

Escalation Criteria

  • !Escalate to incident response and Cisco TAC if the injection returned database content, error-based leakage, or evidence of authentication bypass or data exfiltration.
  • !Escalate to leadership and initiate regulatory/breach notification review if mail metadata, credentials, or PII were accessed via the SQL injection.

Investigation Guide

Related Techniques

[object Object][object Object]

Forensic Artifacts

  • >Cisco ESA web/API access logs (mail_logs, gui_logs) showing SQLi request URLs and bodies
  • >Authentication and audit logs indicating unauthorized session creation or auth bypass
  • >Appliance support bundle / configuration snapshot and any database error logs

Tuning Guidance

Baseline the source IPs of sanctioned vulnerability scanners and penetration-testing tools and exclude them, or route their activity to a lower-severity queue. Constrain matching to the ESA management and API URL paths to reduce noise from unrelated email-content fields that legitimately carry SQL keywords (e.g., subject-line search). Where possible, correlate the SQLi signature with a successful HTTP response code and anomalous response size to raise confidence before alerting analysts, and only alert on external source IPs once internal admin subnets are baselined.

Hunting Queries

Hunt for repeated or diverse SQL injection payload attempts across Cisco ESA endpoints to identify probing or successful exploitation of CVE-2026-76461.

Hunting — KQL
kql 
CommonSecurityLog | where DeviceProduct has_any ("Email Security","IronPort","Secure Email") | where RequestURL has_any ("union","select","information_schema","'--","sleep(") | summarize count() by SourceIP, RequestURL, bin(TimeGenerated, 1h) | order by count_ desc
Hunting — SPL
spl 
index=* sourcetype=cisco:esa OR host=*esa* | eval c=lower(_raw) | search c="*union select*" OR c="*information_schema*" OR c="*xp_cmdshell*" | stats count by src_ip, uri_path | sort - count

Atomic Red Team Tests

Test 1 Error-based SQL injection probe against ESA login endpoint
linux

Sends a single-quote and boolean payload to the ESA web login parameter to trigger a database error, simulating CVE-2026-76461 probing (lab/authorized target only).

Command

bash 
curl -sk "https://esa.lab.local/login" --data-urlencode "username=admin' OR '1'='1' -- -" --data-urlencode "password=x"

Cleanup

bash 
echo 'No persistent artifacts created by request; clear local shell history: history -c'

Expected Telemetry

ESA web/API access log entry containing the single-quote/OR payload in the username parameter; WAF/IPS SQLi signature hit.

Expected Detection

kql and spl detections match on the "' or '1'='1" / "'--" signature in the request.

Test 2 UNION-based SQL injection against ESA API
linux

Issues a UNION SELECT payload against a simulated ESA API query parameter to emulate data-extraction attempts.

Command

bash 
curl -sk "https://esa.lab.local/api/v2.0/config/search?q=1%27%20UNION%20SELECT%20username,password%20FROM%20users--"

Cleanup

bash 
history -c

Expected Telemetry

HTTP request log with 'UNION SELECT' in the URL query string against an /api/ endpoint on the ESA appliance.

Expected Detection

All seven SIEM queries match the 'union select' + information disclosure signature on an /api/ path.

Test 3 Time-based blind SQL injection against ESA
linux

Sends a time-delay payload (SLEEP) to a simulated ESA parameter to emulate blind SQL injection enumeration.

Command

bash 
curl -sk "https://esa.lab.local/csa/search" --data-urlencode "term=widget' AND SLEEP(5)-- -"

Cleanup

bash 
history -c

Expected Telemetry

ESA web log entry containing 'SLEEP(' time-delay payload; server response latency of ~5s recorded in proxy logs.

Expected Detection

kql/spl/elastic_eql detections match the 'sleep(' time-based SQLi signature.

Related Detections

Tactic Hubs

TA0001Initial AccessTA0009Collection

Related Techniques

T1190Exploit Public-Facing ApplicationT1213Data from Information Repositories

Same Tactic: Initial Access

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