Serv-U Remote Memory Escape Vulnerability
CVE-2021-35211

10CRITICAL

Key Information:

Vendor

Solarwinds
Status
Serv-u Managed File Transfer Server And Serv-u Secured Ftp
Vendor
CVE Published:
14 July 2021

Badges

💰 Ransomware👾 Exploit Exists🟡 Public PoC🟣 EPSS 94%🦅 CISA Reported

What is CVE-2021-35211?

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.

CISA has reported CVE-2021-35211

CISA provides regional cyber and physical services to support security and resilience across the United States. CISA monitor the most dangerious vulnerabilities and have identifed CVE-2021-35211 as being exploited and is known by the CISA as enabling ransomware campaigns.

The CISA's recommendation is: Apply updates per vendor instructions.

Affected Version(s)

Serv-U Managed File Transfer Server and Serv-U Secured FTP Windows SolarWinds Serv-U < 15.2.3 HF1

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2021-35211 - Proof of Concept

CVE-2021-35211
Created by BishopFox

Serv-U-CVE-2021-35211
Created by NattiSamson

References

https://www.solarwinds.com/trust-center/security-advisori...
x_refsource_MISC
https://www.microsoft.com/security/blog/2021/07/13/micros...
x_refsource_MISC

EPSS Score

94% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
10
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Changed

Timeline

  • 🟡

    Public PoC available

  • 💰

    Used in Ransomware

  • 👾

    Exploit known to exist

  • 🦅

    CISA Reported

  • Vulnerability published

  • Vulnerability Reserved

Credit

SolarWinds would like to thank the Microsoft Threat Intelligence Center (MSTIC) and Microsoft Offensive Security Research teams for reporting on the issue in a responsible manner.
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CVE-2021-35211 : Serv-U Remote Memory Escape Vulnerability