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SolarWinds Patches Serv-U Vulnerability Propagating Log4j Attacks

SolarWinds this week released patches for a Serv-U vulnerability that Microsoft says has been abused for the propagation of Log4j attacks.

SolarWinds this week released patches for a Serv-U vulnerability that Microsoft says has been abused for the propagation of Log4j attacks.

A multi-protocol file server, SolarWinds Serv-U can be used for sending/receiving files to/from systems on the network. Administrators can create accounts for users and give them permissions to access specific files and folders stored on the server or another network resource.

Tracked as CVE-2021-35247, this input validation bug allows an attacker to build a query based on a given input and then send the query over the network, without sanitization, according to Microsoft, whose researchers discovered the flaw.

“The Serv-U web login screen to LDAP authentication was allowing characters that were not sufficiently sanitized,” SolarWinds notes.

SolarWinds resolved the security error by updating the input mechanism, so that it performs additional validation and sanitization.

According to Microsoft, the vulnerability was identified while monitoring threats exploiting the Log4j vulnerabilities, when some attacks were observed being propagated via CVE-2021-35247.

Thus, the tech giant encourages organizations that use Serv-U to apply the available security updates as soon as possible.

SolarWinds Serv-U 15.3 is the first version of the server to contain patches for the bug. Serv-U 15.2.5 and previous versions are vulnerable.

Related: SolarWinds Hackers Use New Malware in Recent Attacks

Related: Microsoft Says SolarWinds Serv-U Zero-Day Exploited by Chinese Group

Related: Microsoft Spots Multiple Nation-State APTs Exploiting Log4j Flaw

Related: Log4Shell Tools and Resources for Defenders – Continuously Updated

Written By

Ionut Arghire is an international correspondent for SecurityWeek.

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