Link following in Western Digital My Cloud devices
| Risk | High |
| Patch available | YES |
| Number of vulnerabilities | 1 |
| CVE-ID | CVE-2021-3310 |
| CWE-ID | CWE-59 |
| Exploitation vector | Network |
| Public exploit | Public exploit code for vulnerability #1 is available. |
| Vulnerable software |
My Cloud EX2 Ultra Hardware solutions / Other hardware appliances My Cloud Mirror Gen 2 Hardware solutions / Other hardware appliances My Cloud EX4100 Hardware solutions / Other hardware appliances My Cloud PR2100 Hardware solutions / Other hardware appliances My Cloud PR4100 Hardware solutions / Other hardware appliances My Cloud DL2100 Hardware solutions / Other hardware appliances My Cloud DL4100 Hardware solutions / Other hardware appliances My Cloud EX2100 Hardware solutions / Other hardware appliances My Cloud (P/N: WDBCTLxxxxxx-10) Hardware solutions / Other hardware appliances |
| Vendor | Western Digital |
Security Bulletin
This security bulletin contains one high risk vulnerability.
1) Link following
EUVDB-ID: #VU51481
Risk: High
CVSSv4.0: 8.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Amber]
CVE-ID: CVE-2021-3310
CWE-ID:
CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to the affected software mishandle Symbolic Link Following within the SMB and AFP services. A remote attacker can create a symlink to read arbitrary files and gain access to sensitive information or execute arbitrary code on the system.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMy Cloud EX2 Ultra: All versions
My Cloud Mirror Gen 2: All versions
My Cloud EX4100: All versions
My Cloud PR2100: All versions
My Cloud PR4100: All versions
My Cloud DL2100: All versions
My Cloud DL4100: All versions
My Cloud EX2100: All versions
My Cloud (P/N: WDBCTLxxxxxx-10): All versions
CPE2.3- cpe:2.3:h:western_digital:my_cloud_ex2_ultra:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_mirror_gen_2:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_ex4100:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_pr2100:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_pr4100:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_dl2100:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_dl4100:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_ex2100:*:*:*:*:*:*:*:*
- cpe:2.3:h:western_digital:my_cloud_p_n_wdbctlxxxxxx-10:*:*:*:*:*:*:*:*
https://www.westerndigital.com/support/productsecurity/wdc-21002-my-cloud-firmware-version-5-10-122
https://www.zerodayinitiative.com/advisories/ZDI-21-277/
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
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.
