SonicWall Confirms Active Exploitation of Flaws Affecting Multiple Appliance Models

CVE-2021-20035 is an OS command injection flaw (CWE-78) caused by improper neutralization of special elements in the management interface of SonicWall SMA100 series appliances. A remote attacker who has authenticated with low-level privileges can inject arbitrary operating system commands, which are executed on the appliance as the 'nobody' user. Per the CVSS scoring, the primary impact is on availability, potentially leading to denial of service, though command execution on the appliance could facilitate further abuse. The flaw affects SMA 200, 210, 400, 410, and 500v firmware. CISA added it to the Known Exploited Vulnerabilities catalog on 2025-04-16, and related reporting describes ongoing attacks against SonicWall SMA 100 devices — including by threat group UNC6148 deploying the OVERSTEP rootkit and tailored backdoor malware, some against fully patched appliances — so defenders should treat this as actively exploited.

Do: Patch to the fixed firmware release specified in the SonicWall advisory for your SMA model as soon as possible; federal agencies must follow the BOD 22-01 mitigation deadline per the CISA KEV required action. Restrict the management interface to trusted networks, enforce MFA on the portal, and hunt for signs of compromise such as the OVERSTEP rootkit, unexpected persistence, or unfamiliar accounts, since reporting indicates tailored backdoor malware in recent SMA 100 attacks.

SonicWall SMA100 appliances contain an OS command injection flaw (CWE-78) caused by improper neutralization of special elements in the SSL-VPN management interface. A remote attacker who is already authenticated with administrative privileges can submit crafted input containing special characters, causing arbitrary operating system commands to be executed on the appliance. Injected commands run as the low-privilege 'nobody' user, which limits immediate access but still yields high-impact confidentiality, integrity, and availability outcomes (CVSS 7.2) and can provide a foothold for further compromise. Affected products are the SMA 200, SMA 210, SMA 400, and SMA 410 appliance firmware and the SMA 500v virtual appliance firmware. The flaw carries a high EPSS score (75.1%, 99th percentile), was added to CISA's Known Exploited Vulnerabilities catalog on 2025-05-01, and reporting indicates both SonicWall and CISA have confirmed active in-the-wild exploitation of this and related SMA100 flaws.

Do: Upgrade affected SMA100 appliances (SMA 200/210/400/410 and SMA 500v) to the latest vendor-patched firmware per SonicWall's advisory, as required under CISA KEV/BOD 22-01 timelines. Until patched, restrict access to the SSL-VPN management interface to trusted networks and enforce MFA on administrative accounts, since exploitation requires an authenticated administrative session. Given confirmed in-the-wild exploitation, review appliance logs for unauthorized administrative activity or command execution and rotate credentials if compromise is suspected.

CVE-2024-38475 is an improper escaping of output flaw (CWE-116) in the mod_rewrite module of the Apache HTTP Server. It is triggered when mod_rewrite maps a request URL to a filesystem location and mishandles encoded characters, allowing a crafted request to reach files that the server is permitted to serve but that were never intentionally or directly reachable by any URL. An attacker can abuse this to disclose source code (for example, serving raw application files) or, depending on the server's configuration and handlers, achieve code execution. Any Apache HTTP Server deployment that uses mod_rewrite is potentially affected; the source data does not specify the vulnerable version range. The flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2025-05-01, confirming exploitation in the wild, and EPSS assigns it a 100% probability of exploitation within 30 days (100th percentile), though no public proof-of-concept is known and ransomware use is unconfirmed.

Do: Inventory Apache HTTP Server deployments, prioritize internet-facing ones, and check whether mod_rewrite is in use (RewriteRule directives in server config, virtual hosts, or .htaccess files); upgrade to the vendor's fixed release, 2.4.60 or later. If immediate upgrade is not possible, follow vendor guidance to harden or constrain mod_rewrite rules, and treat the issue as actively exploited per CISA KEV, applying BOD 22-01 mitigations for cloud service usage or discontinuing use if mitigation is unavailable.