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LDAP user enumeration with paging support #141

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167 changes: 97 additions & 70 deletions AD-BOF/DCSync-BOF/util/ldap_syncall.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,20 @@ DECLSPEC_IMPORT void* __cdecl MSVCRT$memset(void* dest, int c, size_t count);
DECLSPEC_IMPORT size_t __cdecl MSVCRT$strlen(const char* str);
DECLSPEC_IMPORT char* __cdecl MSVCRT$strcpy(char* dest, const char* src);

// Import required WLDAP32 paging functions
typedef VOID* PLDAPSearch;
struct l_timeval { LONG tv_sec; LONG tv_usec; };
DECLSPEC_IMPORT PLDAPSearch WLDAP32$ldap_search_init_pageA(LDAP*, const char*, ULONG, const char*, char*[], ULONG, LDAPControlA**, LDAPControlA**, ULONG, ULONG, VOID*);
DECLSPEC_IMPORT ULONG WLDAP32$ldap_get_next_page_s(LDAP*, PLDAPSearch, struct l_timeval*, ULONG, ULONG*, LDAPMessage**);
DECLSPEC_IMPORT ULONG WLDAP32$ldap_search_abandon_page(LDAP*, PLDAPSearch);

#ifndef LDAP_NO_LIMIT
#define LDAP_NO_LIMIT 0
#endif
#ifndef LDAP_NO_RESULTS_RETURNED
#define LDAP_NO_RESULTS_RETURNED 0x5e
#endif

// Structure to hold user information
typedef struct _USER_INFO {
char* distinguishedName;
Expand All @@ -33,89 +47,102 @@ USER_INFO* EnumerateAllUsers(LDAP* ld, const char* searchBase, int* userCount, i
// If onlyUsers=1, filter to SAM_USER_OBJECT (0x30000000) and SAM_TRUST_ACCOUNT (0x30000002) only
char* filter = onlyUsers ? "(&(objectClass=user)(|(sAMAccountType=805306368)(sAMAccountType=805306370)))" : "(objectClass=user)";
char* attrs[] = { "distinguishedName", "sAMAccountName", "objectGUID", NULL };

// Search for all user objects
ULONG result = WLDAP32$ldap_search_s(

USER_INFO* users = NULL;
int capacity = 0;
int index = 0;
ULONG totalCount = 0;

PLDAPSearch pageHandle = WLDAP32$ldap_search_init_pageA(
ld,
(char*)searchBase,
searchBase,
LDAP_SCOPE_SUBTREE,
filter,
attrs,
0,
&searchResult
NULL, NULL,
0,
LDAP_NO_LIMIT,
NULL
);

if (result != LDAP_SUCCESS) {
BeaconPrintf(CALLBACK_ERROR, "[-] Failed to enumerate users: 0x%x", result);
return NULL;
}

// Count entries
int count = WLDAP32$ldap_count_entries(ld, searchResult);
if (count <= 0) {
BeaconPrintf(CALLBACK_ERROR, "[-] No users found in domain");
WLDAP32$ldap_msgfree(searchResult);
return NULL;
}

// Allocate array for user info
USER_INFO* users = (USER_INFO*)MSVCRT$malloc(count * sizeof(USER_INFO));
if (!users) {
BeaconPrintf(CALLBACK_ERROR, "[-] Failed to allocate memory for user list");
WLDAP32$ldap_msgfree(searchResult);

if (!pageHandle) {
BeaconPrintf(CALLBACK_ERROR, "[-] Failed to enumerate users: ldap_search_init_page failed");
return NULL;
}
MSVCRT$memset(users, 0, count * sizeof(USER_INFO));

// Iterate through entries
int index = 0;
entry = WLDAP32$ldap_first_entry(ld, searchResult);

while (entry && index < count) {
// Get distinguishedName
char** dnValues = WLDAP32$ldap_get_values(ld, entry, "distinguishedName");
if (dnValues && dnValues[0]) {
size_t len = MSVCRT$strlen(dnValues[0]) + 1;
users[index].distinguishedName = (char*)MSVCRT$malloc(len);
if (users[index].distinguishedName) {
MSVCRT$strcpy(users[index].distinguishedName, dnValues[0]);

ULONG result;
while ((result = WLDAP32$ldap_get_next_page_s(ld, pageHandle, NULL, 1000, &totalCount, &searchResult)) == LDAP_SUCCESS) {

// Count entries
int count = WLDAP32$ldap_count_entries(ld, searchResult);

// Allocate/grow array for user info
if (count > 0 && index + count > capacity) {
int newCapacity = index + count;
USER_INFO* tmp = (USER_INFO*)MSVCRT$realloc(users, newCapacity * sizeof(USER_INFO));
if (!tmp) {
BeaconPrintf(CALLBACK_ERROR, "[-] Failed to allocate memory for user list");
WLDAP32$ldap_msgfree(searchResult);
break;
}
WLDAP32$ldap_value_free(dnValues);
users = tmp;
MSVCRT$memset(users + capacity, 0, (newCapacity - capacity) * sizeof(USER_INFO));
capacity = newCapacity;
}

// Get sAMAccountName
char** samValues = WLDAP32$ldap_get_values(ld, entry, "sAMAccountName");
if (samValues && samValues[0]) {
size_t len = MSVCRT$strlen(samValues[0]) + 1;
users[index].samAccountName = (char*)MSVCRT$malloc(len);
if (users[index].samAccountName) {
MSVCRT$strcpy(users[index].samAccountName, samValues[0]);

// Iterate through entries
entry = WLDAP32$ldap_first_entry(ld, searchResult);

while (entry && index < capacity) {
// Get distinguishedName
char** dnValues = WLDAP32$ldap_get_values(ld, entry, "distinguishedName");
if (dnValues && dnValues[0]) {
size_t len = MSVCRT$strlen(dnValues[0]) + 1;
users[index].distinguishedName = (char*)MSVCRT$malloc(len);
if (users[index].distinguishedName) {
MSVCRT$strcpy(users[index].distinguishedName, dnValues[0]);
}
WLDAP32$ldap_value_free(dnValues);
}
WLDAP32$ldap_value_free(samValues);
}

// Get objectGUID
struct berval** guidValues = WLDAP32$ldap_get_values_len(ld, entry, "objectGUID");
if (guidValues && guidValues[0] && guidValues[0]->bv_len == sizeof(GUID)) {
MSVCRT$memcpy(&users[index].objectGuid, guidValues[0]->bv_val, sizeof(GUID));
WLDAP32$ldap_value_free_len(guidValues);
}

// Only count users that have all required fields
if (users[index].distinguishedName && users[index].samAccountName) {
index++;
} else {
// Free incomplete entry
if (users[index].distinguishedName) MSVCRT$free(users[index].distinguishedName);
if (users[index].samAccountName) MSVCRT$free(users[index].samAccountName);
MSVCRT$memset(&users[index], 0, sizeof(USER_INFO));

// Get sAMAccountName
char** samValues = WLDAP32$ldap_get_values(ld, entry, "sAMAccountName");
if (samValues && samValues[0]) {
size_t len = MSVCRT$strlen(samValues[0]) + 1;
users[index].samAccountName = (char*)MSVCRT$malloc(len);
if (users[index].samAccountName) {
MSVCRT$strcpy(users[index].samAccountName, samValues[0]);
}
WLDAP32$ldap_value_free(samValues);
}

// Get objectGUID
struct berval** guidValues = WLDAP32$ldap_get_values_len(ld, entry, "objectGUID");
if (guidValues && guidValues[0] && guidValues[0]->bv_len == sizeof(GUID)) {
MSVCRT$memcpy(&users[index].objectGuid, guidValues[0]->bv_val, sizeof(GUID));
WLDAP32$ldap_value_free_len(guidValues);
}

// Only count users that have all required fields
if (users[index].distinguishedName && users[index].samAccountName) {
index++;
} else {
// Free incomplete entry
if (users[index].distinguishedName) MSVCRT$free(users[index].distinguishedName);
if (users[index].samAccountName) MSVCRT$free(users[index].samAccountName);
MSVCRT$memset(&users[index], 0, sizeof(USER_INFO));
}

entry = WLDAP32$ldap_next_entry(ld, entry);
}

entry = WLDAP32$ldap_next_entry(ld, entry);

WLDAP32$ldap_msgfree(searchResult);
searchResult = NULL;
}
WLDAP32$ldap_msgfree(searchResult);

WLDAP32$ldap_search_abandon_page(ld, pageHandle);

*userCount = index;
BeaconPrintf(CALLBACK_OUTPUT, "[+] Successfully enumerated %d users", index);

Expand Down