CVE-2023-5868

What it actually does

The flaw allows remote authenticated users to disclose portions of PostgreSQL server memory by calling aggregate functions with 'unknown' type arguments from string literals, resulting in excessive data output.

Why it matters to the business

Attackers with database access could leak sensitive information such as credentials or confidential data from server memory, raising the risk of further compromise or regulatory penalties.

How an attack unfolds

An attacker with valid database credentials connects to a PostgreSQL instance and issues queries using aggregate functions on string literals without explicit type designation, triggering the server to return additional memory bytes in the response.

How to fix it

Upgrade all PostgreSQL installations to a version containing commit fd851f9e4a13d81cccc4ac5d6059d732c7518111 or later to correct the excessive data output in aggregate function handling.

How to confirm the fix worked

Confirm the running PostgreSQL binary or source includes the referenced fix commit, then attempt reproduction queries with unknown-type arguments and verify that responses contain only expected data without memory leakage.

Typical attack path

1. Obtain valid database credentials with login privileges
2. Connect to the target PostgreSQL instance over the network
3. Execute crafted queries invoking aggregate functions on untyped string literals
4. Parse responses to extract and analyze disclosed memory contents

How to detect it

Review PostgreSQL query logs and audit trails for aggregate function calls involving string literals without type casts, and inspect result sets for unexpected binary or memory-like content.

What your security team should do

• Apply the patch commit to all PostgreSQL deployments without delay
• Restrict database user privileges to the minimum required for operations
• Enable detailed query logging and review for suspicious aggregate function usage