China-linked Salt Typhoon Exploits Critical Cisco Vulnerability to Target Canadian Telecom
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2023-20198 | Unauthenticated Privilege Escalation in Cisco IOS XE Web UI (Actively Exploited) CVE-2023-20198 is a critical (CVSS 10.0) unauthenticated privilege escalation flaw in the web UI of Cisco IOS XE software, triggered by sending crafted network requests to the exposed web management interface. An attacker with no credentials can use the flaw to gain initial access and issue a privilege 15 command, creating a local user with normal login access; the attacker then chained CVE-2023-20273 (CVSS 7.2) to elevate that account to root and write an implant to the file system. Successful exploitation yields full administrative control of the device, including persistence via the planted implant, on Cisco IOS XE devices with the web UI enabled and reachable from the internet or untrusted networks, including Rockwell Automation Allen-Bradley Stratix 5200 and 5800 switches running IOS XE. Exploitation is confirmed in the wild: the flaw was added to CISA's KEV on 2023-10-16 with a BOD 23-02 directive, EPSS stands at 99.6% (100th percentile), and ongoing campaigns (including the 'BADCANDY' activity flagged by Australia's ASD and Cisco-related telecom intrusions attributed to Salt Typhoon) have been reported. Do: Upgrade affected devices to the fixed releases listed in Cisco's advisory (use Cisco's Software Checker) and, as immediate mitigation, disable the web UI or restrict it to trusted networks/addresses only. Check for compromise by looking for unexpected local user accounts and the implant artifacts Cisco identified (unexpected cisco_tac_alarm.log and cisco_tac.log files in /tmp or /usr/binos/conf), and immediately report positive findings to CISA per BOD 23-02. Keep in mind that patching alone does not remove a root implant, so devices with evidence of compromise should be reimaged or otherwise cleaned per vendor instructions. | 10.0 | 100% | KEV |
| large≈40,000–50,000 internet-exposed IOS XE devices at the time of disclosure (public scan data), within an IOS XE install base in the millions | |
| CVE-2023-20273 | Authenticated Command Injection (Root) in Cisco IOS XE Web UI CVE-2023-20273 is an OS command injection flaw (CWE-78) in the web UI feature of Cisco IOS XE Software, caused by insufficient input validation. An authenticated, remote attacker triggers it by sending crafted input to the web UI, and a successful exploit injects commands that run on the underlying operating system with root privileges, yielding full device compromise (in the October 2023 mass-exploitation campaign it was typically chained with the unauthenticated CVE-2023-20198 to obtain initial access and install a persistent implant). Any Cisco IOS XE device with the web UI enabled and reachable from the internet or an untrusted network is affected; this data does not specify the affected release ranges, which are enumerated in Cisco's advisory. Exploitation is confirmed in the wild: CISA added the flaw to the KEV on 2023-10-23 with BOD 23-02 response actions, EPSS is ~90% (100th percentile), and IOS XE edge devices remain recurring targets of Chinese-nexus espionage campaigns (e.g., Salt Typhoon activity against telecoms). Do: Upgrade affected devices to a fixed IOS XE release per Cisco's advisory; as an interim mitigation, disable the HTTP/HTTPS server (ip http server / ip https server) or restrict Web UI access to trusted hosts only. Per BOD 23-02, hunt for compromise on any exposed device — check for unexpected level-15 local accounts and the implant.lua backdoor in flash memory — and immediately report positive findings to CISA. | 7.2 | 90% | KEV |
| mass≈100,000+ internet-exposed IOS XE devices (public scans observed ~40,000+ compromised within days of disclosure) |
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Ravie LakshmananJun 24, 2025Cyber Espionage / Chinese Hackers
The Canadian Centre for Cyber Security and the U.S. Federal Bureau of Investigation (FBI) have issued an advisory warning of cyber attacks mounted by the China-linked Salt Typhoon actors to breach major global telecommunications providers as part of a cyber espionage campaign.
The attackers exploited a critical Cisco IOS XE software (CVE-2023-20198, CVSS score: 10.0) to access configuration files from three network devices registered to a Canadian telecommunications company in mid-February 2025.
The threat actors are also said to have modified at least one of the files to configure a Generic Routing Encapsulation (GRE) tunnel, enabling traffic collection from the network. The name of the targeted company was not disclosed.
Stating that the targeting likely goes beyond the telecommunications sector, the agencies said the targeting of Canadian devices may permit the threat actors to collect information from the compromised networks and use them as leverage to breach additional devices.
"In some cases, we assess that the threat actors' activities were very likely limited to network reconnaissance," per the alert.
The agencies further pointed out that edge network devices continue to be an attractive target for Chinese state-sponsored threat actors looking to breach and maintain persistent access to telecom service providers.
The findings dovetail with an earlier report from Recorded Future that detailed the exploitation of CVE-2023-20198 and CVE-2023-20273 to infiltrate telecom and internet firms in the U.S., South Africa, and Italy, and leveraging the footholds to set up GRE tunnels for long-term access and data exfiltration.
U.K. NCSC Warns of SHOE RACK and UMBRELLA STAND Malware Targeting Fortinet Devices
The development comes as the U.K. National Cyber Security Centre (NCSC) revealed two different malware families dubbed SHOE RACK and UMBRELLA STAND that have been found targeting FortiGate 100D series firewalls made by Fortinet.
While SHOE RACK is a post-exploitation tool for remote shell access and TCP tunneling through a compromised device, UMBRELLA STAND is designed to run shell commands issued from an attacker-controlled server.
The NCSC said it identified some similarities between UMBRELLA STAND and COATHANGER, a backdoor that was previously put to use by Chinese state-backed hackers in a cyber attack aimed at a Dutch armed forces network.
Interestingly, SHOE RACK is partly based on a publicly available tool named reverse_ssh, which, coincidentally, has also been repurposed by a China-nexus threat cluster called PurpleHaze to devise a Windows implant codenamed GoReShell. It's currently not clear if these activities are related.
When reached for comment, SentinelOne researcher Aleksander Milenkoski said GoReShell is the name assigned to a "loosely defined cluster" that encompasses all reverse_ssh-based backdoors, including the artifacts described by the NCSC.
"However, it is important to note that APT groups within the broader Chinese threat landscape frequently share tooling," Milenkoski said. "As a result, the activities involving these samples may be distinct from the activity cluster tracked [...] as PurpleHaze, despite similarities in used malware."
(The story was updated after publication to include a response from SentinelOne.)
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