Buffer overflow in Tor - CVE-2017-8821
Published: December 3, 2017 / Updated: July 17, 2020
Vulnerability identifier: #VU31387
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2017-8821
CWE-ID: CWE-119
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, an attacker can cause a denial of service (application hang) via crafted PEM input that signifies a public key requiring a password, which triggers an attempt by the OpenSSL library to ask the user for the password, aka TROVE-2017-011.
Affected software
Tor
Fedora
tor
Fedora
tor
How to mitigate CVE-2017-8821
Install update from vendor's website.
Tor - update to 0.3.1.9
tor - addressed in versions 0.2.9.14-1.el6, 0.2.9.14-1.el7, 0.3.1.9-1.fc26, 0.3.1.9-1.fc27
tor - addressed in versions 0.2.9.14-1.el6, 0.2.9.14-1.el7, 0.3.1.9-1.fc26, 0.3.1.9-1.fc27