Web/SQL Application Logs: SQL Error Strings Indicative of Injection Probing

Flags SQL error log messages with injection-probing syntax/quoting/UNION mismatch keywords.

FreeReviewedSigma · High · v5

Product: sql
Category: application
Author: Bjoern Kimminich (SigmaHQ), DRL 1.1
Published: 2017-11-27
Updated: 2026-07-31

ATT&CK techniques

Initial Access

Recon
Resource Dev
Initial Access
- T1190Exploit Public-Facing Application
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule matches application SQL error messages that commonly appear when an attacker probes for SQL injection (e.g., unterminated quotes, SQL syntax errors, and UNION-related column count mismatches). Such errors can be triggered by crafted inputs used to test whether database queries are susceptible to injection. It relies on application logs from SQL-producing systems containing the specific error text captured by the rule keywords.

Reporting behind it

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Web/SQL Application Logs: SQL Error Strings Indicative of Injection Probing

Pivot detection · T1190 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

sql-error-message-keywords-indicating-potential-injection-probing-8a670c6d

title: "Web/SQL Application Logs: SQL Error Strings Indicative of Injection Probing"
id: b08f4092-77ef-4691-a2e0-f29f5b1f199d
status: test
description: This rule matches application SQL error messages that commonly appear when an attacker probes for SQL injection (e.g., unterminated quotes, SQL syntax errors, and UNION-related column count mismatches). Such errors can be triggered by crafted inputs used to test whether database queries are susceptible to injection. It relies on application logs from SQL-producing systems containing the specific error text captured by the rule keywords.
references:
  - http://www.sqlinjection.net/errors
  - https://github.com/SigmaHQ/sigma/blob/master/rules/application/sql/app_sqlinjection_errors.yml
author: Bjoern Kimminich, Huntrule Team
date: 2017-11-27
modified: 2023-02-12
tags:
  - attack.initial-access
  - attack.t1190
logsource:
  category: application
  product: sql
  definition: "Requirements: application error logs must be collected (with LOG_LEVEL ERROR and above)"
detection:
  keywords:
    - quoted string not properly terminated
    - You have an error in your SQL syntax
    - Unclosed quotation mark
    - 'near "*": syntax error'
    - SELECTs to the left and right of UNION do not have the same number of result columns
  condition: keywords
falsepositives:
  - A syntax error in MySQL also occurs in non-dynamic (safe) queries if there is an empty in() clause, that may often be the case.
level: high
license: DRL-1.1
related:
  - id: 8a670c6d-7189-4b1c-8017-a417ca84a086
    type: derived

Convert

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