sftpgo: Use of Password Hash With Insufficient Computational Effort
CVE-2022-36071 is a high-severity use of password hash with insufficient computational effort vulnerability in sftpgo from Drakkan, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected sftpgo versions: >= 2.2.0, < 2.3.4. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of sftpgo you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.3 | High | CNA (github.com) |
| CVSS 3.1 | 8.1 | High | NVD |
Official description
SFTPGo is configurable SFTP server with optional HTTP/S, FTP/S and WebDAV support. SFTPGo WebAdmin and WebClient support login using TOTP (Time-based One Time Passwords) as a secondary authentication factor. Because TOTPs are often configured on mobile devices that can be lost, stolen or damaged, SFTPGo also supports recovery codes. These are a set of one time use codes that can be used instead of the TOTP. In SFTPGo versions from version 2.2.0 to 2.3.3 recovery codes can be generated before enabling two-factor authentication. An attacker who knows the user's password could potentially generate some recovery codes and then bypass two-factor authentication after it is enabled on the account at a later time. This issue has been fixed in version 2.3.4. Recovery codes can now only be generated after enabling two-factor authentication and are deleted after disabling it.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Password Hash With Insufficient Computational Effort
The product generates a hash for a password, but it uses a scheme that does not provide a sufficient level of computational effort that would make password cracking attacks infeasible or expensive.
How developers prevent this class of flaw
- When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for preventing common attacks.
More Use of Password Hash With Insufficient Computational Effort vulnerabilities (CWE-916)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/drakkan/sftpgo/security/advisories/GHSA-54qx-8p8w-xhg8Mitigation, Third Party Advisory
Patches and release notes
- github.com/drakkan/sftpgo/issues/965Exploit, Issue Tracking, Third Party Advisory
Other vulnerabilities in sftpgo
- 8.1 High severity
- 7.5 High severity
Spotted an error? Tell us.