Actively exploited · Published Jul 14, 2021 · Assigned by SolarWinds
CVE-2021-35211Serv-U Remote Memory Escape Vulnerability
Critical 9.0 Exploited Ransomware
In plain English
A critical-severity out-of-bounds write in Serv-U Managed File Transfer Server and Serv-U Secured FTP from SolarWinds. Attackers are actively exploiting it in the wild (listed by CISA on November 3, 2021). It has been used in ransomware campaigns. The chance it is exploited in the next 30 days is estimated at 91.2% (higher than 99.8% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei, public proof-of-concept code. Apply updates per vendor instructions.
CISA guidance
Apply updates per vendor instructions.
Federal agencies must remediate by Nov 17, 2021.
Official description
Microsoft discovered a remote code execution (RCE) vulnerability in the SolarWinds Serv-U product utilizing a Remote Memory Escape Vulnerability. If exploited, a threat actor may be able to gain privileged access to the machine hosting Serv-U Only. SolarWinds Serv-U Managed File Transfer and Serv-U Secure FTP for Windows before 15.2.3 HF2 are affected by this vulnerability.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| SolarWinds | Serv-U Managed File Transfer Server and Serv-U Secured FTP | SolarWinds Serv-U – before 15.2.3 HF1 |
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
References
- https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35211 x_refsource_MISC
- https://www.microsoft.com/security/blog/2021/07/13/microsoft-discovers-threat-actor-targeting-solarwinds-serv-u-software-with-0-day-exploit x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-35211 government-resource