Microsoft SMB Transaction Parsing RCE Vulnerability

# SPDX-FileCopyrightText: 2012 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.902660");
  script_version("2026-04-28T06:28:06+0000");
  script_cve_id("CVE-2011-0661");
  script_tag(name:"last_modification", value:"2026-04-28 06:28:06 +0000 (Tue, 28 Apr 2026)");
  script_tag(name:"creation_date", value:"2012-03-06 11:57:33 +0530 (Tue, 06 Mar 2012)");
  script_tag(name:"cvss_base", value:"10.0");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:C/I:C/A:C");
  script_name("Microsoft SMB Transaction Parsing RCE Vulnerability");
  script_category(ACT_ATTACK);
  script_copyright("Copyright (C) 2012 Greenbone AG");
  script_family("Windows : Microsoft Bulletins");
  script_dependencies("secpod_ms_smb_accessible_shares.nasl", "os_detection.nasl", "smb_nativelanman.nasl", "netbios_name_get.nasl");
  script_mandatory_keys("SMB/Accessible_Shares", "Host/runs_windows");
  script_require_ports(139, 445);
  script_exclude_keys("SMB/samba");

  script_xref(name:"URL", value:"http://www.securitytracker.com/id?1025329");
  script_xref(name:"URL", value:"http://www.securityfocus.com/bid/47198");
  script_xref(name:"URL", value:"http://www.us-cert.gov/cas/techalerts/TA11-102A.html");
  script_xref(name:"URL", value:"https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-020");

  script_tag(name:"impact", value:"Successful exploitation could allow remote attackers to execute arbitrary
  code on the system.");

  script_tag(name:"affected", value:"- Microsoft Windows 7 SP1 and prior

  - Microsoft Windows 2008 SP2 and prior

  - Microsoft Windows Vista SP2 and prior

  - Microsoft Windows 2008 R2 SP1 and prior

  - Microsoft Windows XP Service Pack 3 and prior

  - Microsoft Windows 2003 Service Pack 2 and prior");

  script_tag(name:"insight", value:"The flaw is due to improper validation of field in SMB request,
  which allows remote attackers to execute arbitrary code on the system by
  sending a malformed SMB request.");

  script_tag(name:"solution", value:"The vendor has released updates. Please see the references for more information.");

  script_tag(name:"summary", value:"This host is missing a critical security update according to
  Microsoft Bulletin MS11-020.");

  script_tag(name:"qod_type", value:"remote_app");
  script_tag(name:"solution_type", value:"VendorFix");

  script_xref(name:"URL", value:"https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-020");
  exit(0);
}

include("smb_nt.inc");
include("host_details.inc");

if( kb_smb_is_samba() ) exit( 0 );

name   = kb_smb_name();
domain = kb_smb_domain();
port   = kb_smb_transport();
login  = kb_smb_login();
pass   = kb_smb_password();

soc1 = open_sock_tcp(port);
if(!soc1){
  exit(0);
}

if(!login)login = "anonymous";
if(!pass) pass = "";

shares = get_kb_list("SMB/Accessible_Shares");
if (isnull(shares))
{
  close(soc1);
  exit(0);
}

prot = smb_neg_prot(soc:soc1);
if(!prot){
  close(soc1);
  exit(0);
}

if(strlen(prot) < 5 ) {
  exit(0);
}

##Currently Only SMB1 is supported, For SMB2 ord(prot[4]) == 254
if(ord(prot[4]) == 254)
{
  close(soc1);
  soc1 = open_sock_tcp(port);
  if(!soc1){
   exit(0);
  }

  r = smb_session_request(soc:soc1, remote:name);
  if(!r) { close(soc1); exit(0); }

  prot = smb_neg_prot_NTLMv1(soc:soc1);
  if(!prot)
  {
    close(soc1);
    exit(0);
  }
}

if(!get_kb_item("login/SMB/kerberos/success")) {
  r = smb_session_setup(soc:soc1, login:login, password:pass, domain:domain, prot:prot);
  if(!r) {
    close(soc1);
    exit(0);
  }
} else {
  kdc = kb_smb_kdc();
  host = kb_smb_hostname();

  if(kdc && host && defined_func("krb5_gss_init")) {

    r = krb5_gss_init();

    context = krb5_gss_prepare_context(kdc:kdc, realm:domain, host:host, service:"cifs", user:login, password:pass);

    if(krb5_is_failure(context)) {
      close(soc1);
      exit(0);
    }
    r = krb5_gss_update_context();

    if(krb5_is_failure(r)) {
      close(soc1);
      exit(0);
    }

    krb5_blob = krb5_gss_update_context_out();
  } else {
    close(soc1);
    exit(0);
  }

  r = smb_session_setup(soc:soc1, login:login, password:pass, domain:domain, prot:prot, kerberos:krb5_blob);
  if(!r) {
    close(soc1);
    exit(0);
  }
}

uid = session_extract_uid(reply:r);
if(!uid)
{
  close(soc1);
  exit(0);
}

foreach share (shares)
{
  r = smb_tconx(soc:soc1, name:name, uid:uid, share:share);

  if(!r){
    continue;
  }

  tid = tconx_extract_tid(reply:r);
  if(!tid)
  {
    continue;
  }

  tid_high = tid / 256;
  tid_low  = tid % 256;
  uid_high = uid / 256;
  uid_low  = uid % 256;

  resp = FindFirst2(socket:soc1, uid:uid, tid:tid, pattern: "\*");

  if (!resp){
    continue;
  }

  foreach file (resp)
  {

    # FindFirst2 returns filenames without a starting slash
    file = "\" + file;

    fid = OpenAndX(socket:soc1, uid:uid, tid:tid, file:file);

    if(!fid){
      continue;
    }

    fid_high = fid / 256;
    fid_low  = fid % 256;

    # nb: SMB Read AndX Request trying to read at a very high offset
    smb_read_andx_req = raw_string(0x00, 0x00, 0x00, 0x3c,           ## Netbios Session
                                   0xff, 0x53, 0x4d, 0x42,           ## Server Component : SMB
                                   0x2e,                             ## SMB Command : Read AndX
                                   0x00, 0x00, 0x00, 0x00,           ## NT Status : Success
                                   0x18, 0x07, 0xc8,                 ## Flags
                                   0x00, 0x00,                       ## Process ID
                                   0x01, 0x00, 0x00, 0x00, 0x00,
                                   0x00, 0x00, 0x00, 0x00, 0x00,     ## Signature & Reserver
                                   tid_low, tid_high,                ## Tree ID
                                   0x33, 0x0c,
                                   uid_low, uid_high, 0x80, 0x01,    ## User ID
                                   0x0c,                             ## Read AndX Word Count
                                   0xff, 0x00,                       ## AndXCommand : No further cmds & Reserved
                                   0x00, 0x00,                       ## AndXoffset
                                   fid_low, fid_high,                ## FID
                                   0xff, 0xff, 0xff, 0xff,           ## Offset : Should be set to large value
                                   0x0a, 0x00, 0x0a, 0x00,           ## Max & Min Count
                                   0xff, 0xff, 0xff, 0xff,           ## File offset & File RW length
                                   0x0a,
                                   0x00, 0xff, 0xff, 0xff, 0x7f,     ##  High Offset
                                   0x00, 0x00, 0x00);                ##  Byte Count

    send(socket:soc1, data: smb_read_andx_req);
    read_resp = smb_recv(socket:soc1);

    smb_close_request(soc:soc1, uid:uid, tid:tid, fid:fid);
    if( strlen( read_resp ) < 13 ) continue;

    ## nb: Check if SMB NT_STATUS is STATUS_INVALID_PARAMETER (0xc000000d)
    if(read_resp && ord(read_resp[9]) == 13 && ord(read_resp[10]) == 0
                 && ord(read_resp[11]) == 0 && ord(read_resp[12]) == 192)
    {
      security_message(port);
      close(soc1);
      exit(0);
    }
  }
}

close(soc1);