CVE-2026-11748

Central Dogma: LDAP injection in SearchFirstActiveDirectoryRealm enables authentication confusion and audit log evasion

Published

2026-09-11

Modified

2026-09-11

EPSS percentile

48%

Aliases

GHSA-98q5-5qh2-7w75

Sources

github-advisory

Summary

# Vulnerability `SearchFirstActiveDirectoryRealm.findUserDn()` substitutes the user-supplied username from the login form into an LDAP search filter template (default `cn={0}`) **without escaping RFC 4515 filter metacharacters** (`*`, `(`, `)`, `\`, NUL). Combined with `SearchControls.setCountLimit(1)` on the same call site, this allows three distinct attack primitives: 1. **Authentication confusion** — typing username `*` causes the realm to construct filter `cn=*`, return the first directory entry (typically a privileged account in AD ordering), and attempt bind against that DN with the attacker's password. 2. **Audit log evasion** — payload `bob)(uid=alice` is recorded verbatim in audit logs while the realm searches with the malformed filter, breaking accountability/compliance (SOX, PCI-DSS, ISO 27001). 3. **Directory enumeration** — wildcards and timing differences allow reconnaissance of OU structure and admin group membership. A repo-wide search for any LDAP escape helper (`escapeLdap`, `encodeFilter`, `escapeFilter`, `ldapEscape`) returns **zero hits** — the defense is not just missing, it was never added. > **Applicability note:** This realm is opt-in. The shipped default LDAP example (`dist/src/conf/shiro.example.ldap.ini`) uses Shiro's `DefaultLdapRealm` with `userDnTemplate` and is **NOT** affected. However, the realm exists precisely to support Active Directory environments where users log in via `sAMAccountName` and the realm must search for the DN first — the canonical LINE corporate AD-backed SSO scenario. Internal deployments using AD-backed login almost certainly select this realm. --- ## Evidence **File:** `server-auth/shiro/src/main/java/com/linecorp/centraldogma/server/auth/shiro/realm/SearchFirstActiveDirectoryRealm.java` **Lines 148–176** on branch `main` @ commit `d64a5151`: ```java @Nullable protected String findUserDn(LdapContextFactory ldapContextFactory, String username) throws NamingException { LdapContext ctx = null; try { ctx = ldapContextFactory.getSystemLdapContext(); final SearchControls ctrl = new SearchControls(); ctrl.setCountLimit(1); // line 156 — returns FIRST match only ctrl.setSearchScope(SearchControls.SUBTREE_SCOPE); ctrl.setTimeLimit(searchTimeoutMillis); final String filter = searchFilter != null ? USERNAME_PLACEHOLDER.matcher(searchFilter) .replaceAll(username) // line 162 — RAW SUBSTITUTION : username; // line 163 final NamingEnumeration result = ctx.search(searchBase, filter, ctrl); ... ``` `USERNAME_PLACEHOLDER = Pattern.compile("\\{0}")`. Default `searchFilter = "cn={0}"`. ### Data flow from HTTP login to vulnerable substitution | Step | Component | |------|-----------| | HTTP login form | `POST /api/v1/login` form field `username` | | `ShiroLoginService.usernamePassword()` (lines 198–223) | applies `loginNameNormalizer` (Unicode lowercase only — **NOT** LDAP escape) | | `Subject.login(new UsernamePasswordToken(username, password))` | Shiro hand-off | | `ActiveDirectoryRealm.doGetAuthenticationInfo` (Shiro core) | calls `queryForAuthenticationInfo0` | | `SearchFirstActiveDirectoryRealm.findUserDn(factory, upToken.getUsername())` | username flows in **verbatim** | ### Repository-wide escape helper grep | Search term | Hits | |-------------|------| | `escapeLdap` | 0 | | `encodeFilter` | 0 | | `escapeFilter` | 0 | | `ldapEscape` | 0 | --- ## PoC Self-contained JUnit 5 test using UnboundID `InMemoryDirectoryServer` (in-process, no external LDAP required). Drop into `server-auth/shiro/src/test/java/com/linecorp/centraldogma/server/auth/shiro/realm/LdapInjectionPoCTest.java` and add `com.unboundid:unboundid-ldapsdk:7.0.0` as a test dependency. > The PoC works by subclassing the realm and overriding `find

Affected packages

Remediation: Upgrade to 0.84.0 or later.

References

• https://github.com/advisories/GHSA-98q5-5qh2-7w75