CVE-2021-27277

This vulnerability allows local attackers to escalate privileges on affected installations of SolarWinds Orion Virtual Infrastructure Monitor 2020.2. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the OneTimeJobSchedulerEventsService WCF service. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-11955.

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• https://documentation.solarwinds.com/en/Success_Center/SAM/Content/Release_Notes/SAM_2020-2-5_release_notes.htm#Fixed
• https://www.zerodayinitiative.com/advisories/ZDI-21-373/
• https://documentation.solarwinds.com/en/Success_Center/SAM/Content/Release_Notes/SAM_2020-2-5_release_notes.htm#Fixed
• https://www.zerodayinitiative.com/advisories/ZDI-21-373/