Patchfirst
CVE-2021-35394 KEVPublic exploit Critical · 9.8 EPSS 99.9%

Realtek Jungle SDK Remote Code Execution Vulnerability

Realtek · Jungle Software Development Kit (SDK)

Summary

Realtek's Jungle Software Development Kit (SDK) versions v2.x through v3.4.14B contain multiple memory corruption flaws and an OS command injection flaw in the 'MP Daemon' diagnostic tool, usually compiled as the 'UDPServer' binary. An unauthenticated attacker with network access can exploit these flaws remotely, with no user interaction or special configuration required, to execute arbitrary commands on the affected device.

Official description · NVD

Realtek Jungle SDK version v2.x up to v3.4.14B provides a diagnostic tool called 'MP Daemon' that is usually compiled as 'UDPServer' binary. The binary is affected by multiple memory corruption vulnerabilities and an arbitrary command injection vulnerability that can be exploited by remote unauthenticated attackers.

Breakdown
69.9 / 100
Exploited
Yes, in CISA KEV
Reports
0
Tactics
4/15

How an attack unfolds

Based on mappings. Select a step to see the evidence.
  1. How attackers get in

  2. What they do

  3. What can follow

First seen exploited 11 days after disclosure.

  1. Disclosedday 0
  2. First seen exploitedVulnCheck KEV evidence+11 days
  3. Added to CISA KEVEU database agrees+4 mo

CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.

techniques

7 , grouped by in kill-chain order 7

Initial AccessTA0001

Exploit Public-Facing Application T1190 Medium
MITRE CTID mapping of the KEV entry · how it is exploited

The vulnerability in Realtek Jungle chipsets is exploited by remote, unauthenticated attackers using UDP packets to a server on port 9034, enabling remote execution of arbitrary commands. The attack involves injecting a shell command that downloads and executes a shell script on the compromised device. This script downloads binaries for various CPU architectures, such as ARM, MIPS, and SuperH, primarily from the Mirai malware family, turning the device into a botnet node. The attack script connects to a malicious IP to download and execute malware, with threats mainly from Mirai, Gafgyt, and Mozi families. It also includes a new DDoS botnet called RedGoBot, developed in Golang. The script uses wget and curl to download botnet clients for different processor architectures. RedGoBot can perform DDoS attacks on various protocols, including HTTP, ICMP, TCP, UDP, VSE, and OpenVPN, upon receiving commands from the threat operator. Additionally, injected commands can write binary payloads to files for execution or reboot the targeted server to cause denial of service.

ExecutionTA0002

Command and Scripting Interpreter T1059 Medium
MITRE CTID mapping of the KEV entry · primary impact
Service Execution T1569.002 Medium
MITRE CTID mapping of the KEV entry · follow-on activity

Command and ControlTA0011

Web Protocols T1071.001 Medium
MITRE CTID mapping of the KEV entry · follow-on activity
Ingress Tool Transfer T1105 Medium
MITRE CTID mapping of the KEV entry · follow-on activity

ImpactTA0040

Resource Hijacking T1496 Medium
MITRE CTID mapping of the KEV entry · follow-on activity
Endpoint Denial of Service T1499 Medium
MITRE CTID mapping of the KEV entry · follow-on activity

Detection

0 rules for this CVE · 432 general rules for its techniques

Rules for this CVE

0 that reference CVE-2021-35394 directly.

CVE-specific rules are not available in this build. Search SigmaHQ ↗

General rules for this CVE’s techniques

These detect the technique in general, not this specific vulnerability.

Exploit Public-Facing ApplicationT1190149 general rules
Command and Scripting InterpreterT105995 general rules
Service ExecutionT1569.00243 general rules
Web ProtocolsT1071.00142 general rules
Ingress Tool TransferT110587 general rules
Resource HijackingT149613 general rules
Endpoint Denial of ServiceT14993 general rules

Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.

What security researchers reported

Not named in any threat report yet

Also mentioned in 50 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

5 links, grouped by NVD tag (4 duplicates merged)
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