CVE-2021-3882

Published: 14 October 2021

LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reverse proxy. By tricking a user to use an unencrypted connection (HTTP), an attacker may be able to obtain the authentication data by capturing network traffic. LedgerSMB 1.8 and newer switched from Basic authentication to using cookie authentication with encrypted cookies. Although an attacker can't access the information inside the cookie, nor the password of the user, possession of the cookie is enough to access the application as the user from which the cookie has been obtained. In order for the attacker to obtain the cookie, first of all the server must be configured to respond to unencrypted requests, the attacker must be suitably positioned to eavesdrop on the network traffic between the client and the server *and* the user must be tricked into using unencrypted HTTP traffic. Proper audit control and separation of duties limit Integrity impact of the attack vector. Users of LedgerSMB 1.8 are urged to upgrade to known-fixed versions. Users of LedgerSMB 1.7 or 1.9 are unaffected by this vulnerability and don't need to take action. As a workaround, users may configure their Apache or Nginx reverse proxy to add the Secure attribute at the network boundary instead of relying on LedgerSMB. For Apache, please refer to the 'Header always edit' configuration command in the mod_headers module. For Nginx, please refer to the 'proxy_cookie_flags' configuration command.

Priority

Cvss 3 Severity Score

6.8

Score breakdown

Status

Package	Release	Status
ledgersmb Launchpad, Ubuntu, Debian	bionic	Not vulnerable (code not present)
	focal	Needed
	hirsute	Ignored (end of life)
	impish	Ignored (end of life)
	jammy	Needs triage
	kinetic	Ignored (end of life, was needs-triage)
	lunar	Ignored (end of life, was needs-triage)
	mantic	Needs triage
	trusty	Ignored (end of standard support)
	upstream	Not vulnerable (debian: Vulnerable code introduced later)
	xenial	Needs triage

Severity score breakdown

Parameter	Value
Base score	6.8
Attack vector	Network
Attack complexity	High
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

References

Join the discussion

Canonical is offering Expanded Security Maintenance

Canonical is offering Ubuntu Expanded Security Maintenance (ESM) for security fixes and essential packages.

Find out more about ESM ›