Multiple vulnerabilities in SolarWinds Serv-U FTP Server
| Risk | High |
| Patch available | YES |
| Number of vulnerabilities | 5 |
| CVE-ID | CVE-2021-25276 CVE-2020-35482 CVE-2020-35481 CVE-2020-27994 CVE-2020-28001 |
| CWE-ID | CWE-276 CWE-79 CWE-94 CWE-22 |
| Exploitation vector | Network |
| Public exploit |
Public exploit code for vulnerability #4 is available. Public exploit code for vulnerability #5 is available. |
| Vulnerable software Subscribe |
Serv-U FTP Server Server applications / File servers (FTP/HTTP) |
| Vendor | SolarWinds |
Security Bulletin
This security bulletin contains information about 5 vulnerabilities.
Updated: 12.02.2021
Updated vulnerability description for #VU50295.
1) Incorrect default permissions
EUVDB-ID: #VU50292
Risk: Low
CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-25276
CWE-ID:
CWE-276 - Incorrect Default Permissions
Exploit availability: No
DescriptionThe vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to incorrect default permissions on the Windows "Users" directory. A local user with access to the system can view contents of files and obtain users' password hashes from the "%ProgramData%\RhinoSoft\Serv-U\Users\<DOMAIN>\" directory.
Install updates from vendor's website.
Vulnerable software versionsServ-U FTP Server: 15.1 - 15.2.1
External linkshttp://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=28396
http://documentation.solarwinds.com/en/success_center/servu/Content/Release_Notes/Servu_15-2-2_release_notes.htm
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
2) Cross-site scripting
EUVDB-ID: #VU50293
Risk: Low
CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-35482
CWE-ID:
CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Exploit availability: No
DescriptionThe disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
MitigationInstall updates from vendor's website.
Vulnerable software versionsServ-U FTP Server: 15.1 - 15.2.1
External linksQ & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
3) Code Injection
EUVDB-ID: #VU50294
Risk: High
CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2020-35481
CWE-ID:
CWE-94 - Improper Control of Generation of Code ('Code Injection')
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to improper input validation. A remote attacker can send a specially crafted request and execute arbitrary macros on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
MitigationInstall updates from vendor's website.
Vulnerable software versionsServ-U FTP Server: 15.1 - 15.2.1
External linksQ & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
4) Path traversal
EUVDB-ID: #VU50295
Risk: Medium
CVSSv3.1: 5.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C]
CVE-ID: CVE-2020-27994
CWE-ID:
CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Exploit availability: Yes
DescriptionThe vulnerability allows a remote user to perform directory traversal attacks.
The vulnerability exists due to input validation error when processing directory traversal sequences passed via the "dir" HTTP GET parameter. A remote user can send a specially crafted HTTP request and read arbitrary files on the system.
Example:
https:///[host]/?Command=List&dir=\..\*.*Mitigation
Install update from vendor's website.
Vulnerable software versionsServ-U FTP Server: 15.1 - 15.2.1
External linksQ & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
5) Stored cross-site scripting
EUVDB-ID: #VU50296
Risk: Low
CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:P/RL:O/RC:C]
CVE-ID: CVE-2020-28001
CWE-ID:
CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Exploit availability: Yes
DescriptionThe disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
MitigationInstall updates from vendor's website.
Vulnerable software versionsServ-U FTP Server: 15.1 - 15.2.1
External linksQ & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.
