Input validation error in Tor - CVE-2017-8819
Published: December 3, 2017 / Updated: August 8, 2020
Vulnerability identifier: #VU37868
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-2017-8819
CWE-ID: CWE-20
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, the replay-cache protection mechanism is ineffective for v2 onion services, aka TROVE-2017-009. An attacker can send many INTRODUCE2 cells to trigger this issue.
Affected software
Tor
Arch Linux
Fedora
tor
Arch Linux
Fedora
tor
How to mitigate CVE-2017-8819
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