CVE-2021-23241

published 2021-01-07

CVE-2021-23241: MERCUSYS Mercury X18G 1.0.5 devices allow Directory Traversal via ../ in conjunction with a loginLess or login.htm URI (for authentication bypass) to the web…

Priority P3 50 medium 5.3 CVSS 3.1

AV N AC L PR N UI N S U C L I N A N

EXPLOIT

MERCUSYS Mercury X18G 1.0.5 devices allow Directory Traversal via ../ in conjunction with a loginLess or login.htm URI (for authentication bypass) to the web server, as demonstrated by the /loginLess/../../etc/passwd URI.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
mercusys	mercury_x18g_firmware	—	—

Detection & IOCs extracted from sources · hover to see the quote

url /loginLess/../../etc/passwd↗

path /loginLess/../../etc/passwd

yara

regex: root:.*:0:0:

• → Send an unauthenticated HTTP GET request to the path /loginLess/../../etc/passwd on the target device. A successful exploitation returns HTTP 200 with a body matching 'root:.*:0:0:', indicating /etc/passwd was read.
• → Authentication bypass is achieved by using the 'loginLess' or 'login.htm' URI prefix in conjunction with directory traversal sequences (../) to access arbitrary files without credentials. ↗

• · Vulnerability is confirmed only on MERCUSYS Mercury X18G firmware version 1.0.5; other versions are not confirmed affected.

CVSS provenance

nvd v3.1 5.3 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

nvd v2.0 5.0 MEDIUM AV:N/AC:L/Au:N/C:P/I:N/A:N

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CWE-22