CVE-2017-13090 Information

Description

The retr.c:fd_read_body() function is called when processing OK responses. When the response is sent chunked in wget before 1.19.2 the chunk parser uses strtol() to read each chunk’s length but doesn’t check that the chunk length is a non-negative number. The code then tries to read the chunk in pieces of 8192 bytes by using the MIN() macro but ends up passing the negative chunk length to retr.c:fd_read(). As fd_read() takes an int argument the high 32 bits of the chunk length are discarded leaving fd_read() with a completely attacker controlled length argument. The attacker can corrupt malloc metadata after the allocated buffer.

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Reference

http://git.savannah.gnu.org/cgit/wget.git/commit/?id=ba6b44f6745b14dce414761a8e4b35d31b176bba http://www.debian.org/security/2017/dsa-4008 http://www.securityfocus.com/bid/101590 http://www.securitytracker.com/id/1039661 https://access.redhat.com/errata/RHSA-2017:3075 https://security.gentoo.org/glsa/201711-06 https://www.synology.com/support/security/Synology_SA_17_62_Wget https://www.viestintavirasto.fi/en/cybersecurity/vulnerabilities/2017/haavoittuvuus-2017-037.html

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8