Skip to content

Back to the catalog

Nicholas Martin (@ndgmlondon) on X
x.comthread

Nicholas Martin (@ndgmlondon) on X

An X post advises auditing every MCP write tool against the database role it actually runs under. A shared service key lets prompt injection trigger unapproved writes, so each agent session should get a read-only role, with a test that writes are denied. Replies note that MCP servers often inherit ambient host credentials or can escalate through a second connection pool, and suggest also testing that another tenant's rows are unreadable with the same role.

TL;DR Run MCP agent sessions under per-session read-only DB roles and test that writes and cross-tenant reads are denied, since shared keys and ambient creds enable prompt-injection writes.

Technologies named here

Techniques named here