CVE-2020-2883: 
Oracle WebLogic Server vulnerability analysis and mitigation

CVE-2020-2883 is a critical deserialization vulnerability affecting Oracle WebLogic Server versions 10.3.6.0.0, 12.1.3.0.0, 12.2.1.3.0, and 12.2.1.4.0. The vulnerability was discovered in early 2020 and patched in Oracle's April 2020 Critical Patch Update. This flaw exists within the Oracle Coherence library, an in-memory data grid solution that handles data compression and decompression (Tenable Blog).

The vulnerability allows unauthenticated remote attackers to execute arbitrary code through the T3 protocol. The specific flaw exists within the Oracle Coherence library due to improper validation of user-supplied data, which can result in deserialization of untrusted data. The vulnerability has received a CVSS v3.0 base score of 9.8 (Critical) with the vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating it can be exploited over the network without requiring privileges or user interaction (ZDI Advisory).

Successful exploitation of this vulnerability can result in complete takeover of the Oracle WebLogic Server. An attacker can leverage this vulnerability to execute code in the context of the service account, potentially gaining full control over the affected system (ZDI Advisory, CISA Alert).

Oracle released patches for CVE-2020-2883 as part of the April 2020 Critical Patch Update. Organizations are strongly advised to apply these patches without delay. For systems that cannot be immediately patched, Oracle has published security guidance to restrict the Oracle WebLogic Server T3/T3S protocol traffic as a temporary mitigation measure (Tenable Blog).

Oracle published a blog post strongly encouraging customers to apply the patches 'without delay' due to active exploitation attempts. The Cybersecurity and Infrastructure Security Agency (CISA) also issued an alert warning users about the active exploitation of this vulnerability in the wild (CISA Alert).