Ldap Injection in Aspnet with Cockroachdb

LDAP Injection in an ASP.NET application that uses CockroachDB as a backend data store occurs when user-supplied input is concatenated into an LDAP query without validation or escaping. CockroachDB, as a distributed SQL database, does not directly parse LDAP, but it can store directory configuration or be queried by the application to support identity lookups. If the application builds LDAP filter strings by inserting unchecked input into attributes like uid or mail, an attacker can manipulate the filter syntax to bypass authentication or extract data.

For example, an attacker might supply a username value of (uid=*) or append additional filter components such as (&(objectClass=person)(mail=*)). Because the filter is constructed by string concatenation, the injected content changes the logical scope of the search, potentially returning multiple entries or bypassing required checks. In ASP.NET, this often happens in authentication modules or custom membership providers that query LDAP before consulting CockroachDB for supplemental user data.

The presence of CockroachDB can amplify impact if the application uses the database to maintain mappings between LDAP identities and application roles. An attacker who manipulates LDAP search results might cause the application to look up a different database row based on the poisoned identifier, leading to authorization mismatches. Moreover, if the application logs LDAP queries or errors to CockroachDB, malicious payloads could be persisted, enabling later reconnaissance or log injection. This combination therefore creates a path where LDAP injection compromises both identity verification and data integrity stored in CockroachDB.

Real-world exploitation patterns mirror the OWASP API Top 10 Broken Object Level Authorization (BOLA) and Injection categories. While LDAP Injection targets the directory service, the downstream data in CockroachDB may be leveraged for privilege escalation if role mappings are tampered with. For instance, an injected filter that returns an alternate user entry could cause the application to issue JWTs or session tokens with incorrect claims, especially when combined with insufficient property-level authorization checks.

Because middleBrick scans the unauthenticated attack surface and tests input validation and authentication controls, it can surface LDAP injection vectors that involve backend data stores like CockroachDB. The scanner does not fix the logic, but its findings highlight the need for strict allowlisting of identifiers and robust schema validation for any data stored in CockroachDB that participates in identity workflows.

Remediation focuses on preventing untrusted input from altering LDAP query structure and ensuring that any interaction with CockroachDB is parameterized and context-aware. In ASP.NET, prefer using the System.DirectoryServices.Protocols API with explicit filter building rather than string concatenation. Treat user input as values only, never as part of the filter syntax.

Example of vulnerable code that concatenates input into an LDAP filter:

string userSuppliedUsername = usernameTextBox.Text;
string filter = $"(uid={userSuppliedUsername})";
var request = new SearchRequest("dc=example,dc=com", filter, SearchScope.Subtree, null);
using var connection = new LdapConnection("ldap.example.com");
connection.Bind();
var response = (SearchResponse)connection.SendRequest(request);

An attacker can set usernameTextBox.Text to *) to return all entries. The fix is to escape special characters and treat the input as a literal value.

Secure version with proper escaping in ASP.NET:

using System.DirectoryServices.Protocols;

string userSuppliedUsername = usernameTextBox.Text;
string escaped = Filter.EscapeFilter(userSuppliedUsername);
string filter = $"(uid={escaped})";
var request = new SearchRequest("dc=example,dc=com", filter, SearchScope.Subtree, null);
using var connection = new LdapConnection("ldap.example.com");
connection.SessionOptions.ProtocolVersion = 3;
connection.Bind();
var response = (SearchResponse)connection.SendRequest(request);

CockroachDB-specific remediation in ASP.NET should use parameterized queries when storing or retrieving identity mappings. Avoid dynamic SQL construction with string interpolation. Use Npgsql with parameters to ensure that identifiers and values are handled safely.

Example of vulnerable CockroachDB interaction in ASP.NET:

using var conn = new NpgsqlConnection(connectionString);
await conn.OpenAsync();
var cmd = new NpgsqlCommand($"SELECT role FROM user_roles WHERE ldap_uid = '{userSuppliedUid}'", conn);
var role = await cmd.ExecuteScalarAsync();

This is susceptible to SQL injection if userSuppliedUid is derived from LDAP results that were themselves manipulated. Always parameterize:

using var conn = new NpgsqlConnection(connectionString);
await conn.OpenAsync();
var cmd = new NpgsqlCommand("SELECT role FROM user_roles WHERE ldap_uid = @uid", conn);
cmd.Parameters.AddWithValue("@uid", ldapUid);
var role = await cmd.ExecuteScalarAsync();

When integrating LDAP and CockroachDB, implement strict allowlists for character classes in identifiers (e.g., alphanumeric and limited punctuation) and validate length. In ASP.NET, centralize identity resolution in a service that separately handles LDAP binding with escaped filters and CockroachDB lookups with parameterized commands. middleBrick’s scans can verify that no raw concatenation remains in authentication paths and that findings align with OWASP API Top 10 Injection and Broken Object Level Authorization guidance.