Information disclosure in nginx

1) Out-of-bounds read

EUVDB-ID: #VU26234

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: N/A

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition when processing rewrite rules with a '\0' character in ngx_http_core_module.c. An attacker with ability to influence a rewrite rule can view memory contents via Location HTTP header.

Successful exploitation of vulnerability requires that an attacker can influence rewrite engine, as demonstrated with OpenResty issue.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

nginx: 0.3.0 - 1.17.6

External links

http://hackerone.com/reports/513236
http://seclists.org/oss-sec/2020/q1/113
http://github.com/nginx/nginx/commit/a5895eb502747f396d3901a948834cd87d5fb0c3

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.