Critical Remote Code Execution Bug in Linux Based OpenWrt OS Affects Millions of Network Devices

Security researcher uncovered a critical remote code execution vulnerability in OpenWrt operating system that allows attackers to inject the malicious payload on the vulnerable systems.

OpenWrt is a Linux based operating system that is mainly used in embedded devices and network routers to route the network traffic and is installed on millions of devices around the globe.

The RCE bug addressed in the package list parse the logic of OpenWrt’s opkg (Opkg Package Manager) fork let package manager ignore the SHA-256 checksums embedded in the signed repository index which allows an attacker to bypass the integrity checking of downloaded .ipk artifacts.

Guido Vranken, a researcher explained that he found this vulnerability initially by chance when he was preparing a Mayhem task for opkg. Mayhem can serve data either from a file or from a network socket.

” I set up a Mayhem task for opkg install attr (attr is a small OpenWRT package), and implicitly, Mayhem was able to find the remote code execution bug, by detecting the memory bugs in the package unpacker. If OpenWRT’s SHA256 verification had worked as intended, opkg would simply discard the package and not process it, and no segmentation faults would transpire,” researcher said.

OpenWRT RCE Vulnerability Exploitation Process

To exploit this RCE vulnerability, the attacker needs to serve compromised packages from a web server and need to intercept communication between the device and or the ability to control the DNS server that used by the device to make point to a web server controlled by the attacker.

In fact, opkg on OpenWrt running as root that allows attackers to gain the write access to the entire file systems and inject the arbitrary code remotely by forged .ipk packages with a malicious payload. 

According to OpenWRT bug fix report “During the attack, a malicious actor needs to pose as MITM, serving a valid and signed package index – e.g. one obtained from – and one or more forged .ipk packages having the same size as specified in the repository index while an `opkg install` command is invoked on the victim system.”

You can also read the complete technical analysis of this vulnerability here.

The vulnerability has been fixed and assigned CVE-2020-7982 and the users are urged to upgrade to the latest OpenWrt version.

How to Update:

The following commands may be used once all repositories have been updated:

 cd /tmp
 opkg update
 opkg download opkg
 zcat ./opkg-lists/openwrt_base | grep -A10 "Package: opkg" | grep SHA256sum
 sha256sum ./opkg_2020-01-25-c09fe209-1_*.ipk

Also Read:

Critical Vulnerability in ppp Daemon Let Hackers Remotely Exploit the Linux Systems & Gain Root Access

RCE Vulnerability in OpenSMTPD Mail Server Let Hackers Exploit The Linux Systems Remotely


BALAJI is an Ex-Security Researcher (Threat Research Labs) at Comodo Cybersecurity. Editor-in-Chief & Co-Founder - Cyber Security News & GBHackers On Security.

View Comments

  • I think you need to also run:

    opkg install opkg_2020-01-25-c09fe209-1_mips_24kc.ipk

    to upgrade opkg.

Recent Posts

Cryptojacking Campaign Infected Online Thesaurus With Over 5 Million Visitors

Students, authors, and anybody else wishing to improve their vocabulary and language abilities frequently utilize…

1 day ago

Gold Melody Attacking Organizations With Burp Extension, Mimikatz, and Other Tools

The financially motivated GOLD MELODY threat group has been active at least since 2017, attacking…

2 days ago

MOVEit Transfer SQL Injection Let the Attacker Gain Unauthorized Access to the Database

MOVEit transfer service pack has been discovered with three vulnerabilities associated with SQL injections (2)…

2 days ago

LUCR-3 Attacking Fortune 2000 Companies Using Victims’ Own Tools & Apps

A new financially motivated threat group named “LUCR-3” has been discovered targeting organizations to steal…

2 days ago

Is QakBot Malware Officially Dead?

Only a few malware families can claim to have persisted for nearly twenty years, and…

2 days ago

System Admin Pleads Guilty for Selling Pirated Business Phone Software Licenses

For taking part in a large international scheme to earn millions of dollars by selling pirated…

2 days ago