...
| Code Block | ||
|---|---|---|
| ||
class SecurityIOException extends IOException {/* ... */};
try {
FileInputStream fis = new FileInputStream(System.getenv("APPDATA") + args[0]);
} catch (FileNotFoundException e) {
// Log the exception
throw new SecurityIOException();
}
|
While this exception is less likely to leak useful information than previous noncompliant code examples, it still reveals that the specified file cannot be read. More specifically, the program reacts differently to nonexistent file paths than it does to valid ones, and an attacker can still infer sensitive information about the file system from this program's behavior. Failure to restrict user input leaves the system vulnerable to a brute force attack in which the attacker discovers valid file names with repeated queries that collectively cover the space of possible file names; queries that result in the sanitized message exclude the requested file, the remaining possibilities represent the actual files.
...
| Code Block | ||
|---|---|---|
| ||
class ExceptionExample {
public static void main(String[] args) {
File file = null;
try {
file = new File(System.getenv("APPDATA") + args[0]).getCanonicalFile();
if (!file.getPath().startsWith("c:\\homepath")) {
System.out.println("Invalid file");
return;
}
} catch (IOException x) {
System.out.println("Invalid file");
return;
}
try {
FileInputStream fis = new FileInputStream( file);
} catch (FileNotFoundException x) {
System.out.println("Invalid file");
return;
}
}
}
|
...
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="6dcf1bc8c2ce551e-16cdce9e-4a6f4a2d-917bbaf0-5caae31b3efe67ddf5756ae6"><ac:plain-text-body><![CDATA[ | [[MITRE 2009 | AA. Bibliography#MITRE 09]] | [CWE ID 209 | http://cwe.mitre.org/data/definitions/209.html] "Information Exposure Through an Error Message" | ]]></ac:plain-text-body></ac:structured-macro> |
| CWE ID 600 "Uncaught Exception in Servlet" | ||||
| CWE ID 497 "Exposure of System Data to an Unauthorized Control Sphere" |
...
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="baf35f041e9a0f43-6dfad5bd-4fe24c75-ab1bb349-51e268b6daa03f7c0ec4bcee"><ac:plain-text-body><![CDATA[ | [[Gong 2003 | AA. Bibliography#Gong 03]] | 9.1 Security Exceptions | ]]></ac:plain-text-body></ac:structured-macro> |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="b71953e915fcf802-210b2b47-4d6c4b71-a86cbd60-e94cc09040b882c38c0fff58"><ac:plain-text-body><![CDATA[ | [[SCG 2007 | AA. Bibliography#SCG 07]] | Guideline 3-4 Purge sensitive information from exceptions | ]]></ac:plain-text-body></ac:structured-macro> |
...