CVE-2023-32691 – github.com/ginuerzh/gost

Package

Manager: go
Name: github.com/ginuerzh/gost
Vulnerable Version: >=0 <=2.11.5

Severity

Level: Medium

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

CVSS v4.0: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

EPSS: 0.00215 pctl0.44084

Details

ginuerzh/gost vulnerable to Timing Attack [Timing attacks](https://en.wikipedia.org/wiki/Timing_attack) occur when an attacker can guess a secret by observing a difference in processing time for valid and invalid inputs. Sensitive secrets such as passwords, token and API keys should be compared only using a constant-time comparision function. More information on this attack type can be found in [this blog post](https://verboselogging.com/2012/08/20/a-timing-attack-in-action). # Root Cause Analysis In this case, the vulnerability occurs due to the following code. https://github.com/ginuerzh/gost/blob/1c62376e0880e4094bd3731e06bd4f7842638f6a/auth.go#L46-L46 Here, a untrusted input, sourced from a HTTP header, is compared directly with a secret. Since, this comparision is not secure, an attacker can mount a side-channel timing attack to guess the password. # Remediation This can be easily fixed using a constant time comparing function such as `crypto/subtle`'s `ConstantTimeCompare`. An example fix can be found in https://github.com/runatlantis/atlantis/commit/48870911974adddaa4c99c8089e79b7d787fa820 Alternatively, one can apply the patch below ``` From d18cff85e1a565f688f717fd8f2cacea62ff9dbf Mon Sep 17 00:00:00 2001 From: Porcupiney Hairs <porcupiney.hairs@protonmail.com> Date: Sun, 7 May 2023 01:03:33 +0530 Subject: [PATCH] Fix : Timing attack --- auth.go | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/auth.go b/auth.go index 1be96e9..be13f23 100644 --- a/auth.go +++ b/auth.go @@ -2,6 +2,7 @@ package gost import ( "bufio" + "crypto/subtle" "io" "strings" "sync" @@ -43,7 +44,8 @@ func (au *LocalAuthenticator) Authenticate(user, password string) bool { } v, ok := au.kvs[user] - return ok && (v == "" || password == v) + passOk := subtle.ConstantTimeCompare([]byte(password), []byte(v)) == 0 + return ok && (v == "" || passOk) } // Add adds a key-value pair to the Authenticator. -- 2.25.1 ```

Metadata

Created: 2023-05-22T19:47:15Z
Modified: 2023-05-30T06:42:29Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2023/05/GHSA-qjrq-hm79-49ww/GHSA-qjrq-hm79-49ww.json
CWE IDs: ["CWE-203"]
Alternative ID: GHSA-qjrq-hm79-49ww
Finding: F026
Auto approve: 1