A number of crucial vulnerabilities affecting SonicWall’s SMA100 sequence SSL-VPN home equipment, highlighting persistent safety flaws in community infrastructure units.
The vulnerabilities, designated CVE-2025-40596, CVE-2025-40597, and CVE-2025-40598, show basic programming errors that allow pre-authentication assaults in opposition to firmware model 10.2.1.15.
Key Takeaways1. Stack overflow, heap overflow, and XSS in SonicWall SMA100 SSL-VPN units.2. Each overflows triggered with out authentication through malformed HTTP requests.3. Unsafe programming practices proceed in crucial community infrastructure.
CVE-2025-40596: Pre-Authentication Stack Buffer Overflow
In response to WatchTower Labs’ evaluation, the vulnerability represents a basic stack-based buffer overflow triggered by malformed HTTP requests to the /__api__/ endpoint.
The flaw throughout the /usr/src/EasyAccess/bin/httpd binary is liable for processing incoming SSL-VPN connections.
The weak code makes use of an unsafe sscanf operate name that parses user-controlled URI information with out correct bounds checking.
When the system encounters requests starting with /__api__/, it copies consumer enter right into a 0x800-byte stack buffer situated at [rsp+898h+var_878] with out validating enter size.
Exploitation requires minimal effort, achievable by a easy Python one-liner: import requests; requests.get(“
Whereas stack safety mechanisms restrict quick exploitation potential, the vulnerability’s pre-authentication nature in an SSL-VPN context raises vital safety considerations.
CVE-2025-40597: Heap Overflow
The second vulnerability impacts the mod_httprp.so module, seemingly standing for “HTTP Reverse Proxy,” which handles numerous SonicWall-specific HTTP parsing capabilities.
This heap-based buffer overflow happens throughout Host header processing, demonstrating how even “safe” programming practices can fail when applied incorrectly.
The weak code allocates a 128-byte heap chunk through calloc(0x80, 1) earlier than passing it to __sprintf_chk.
Regardless of utilizing the supposedly safer sprintf variant, builders handed -1 (0xFFFFFFFFFFFFFFFF) as the scale parameter, successfully disabling bounds checking solely.
This configuration permits attackers to overflow the allotted heap chunk by sending outsized Host headers: import requests; requests.get(“ headers={‘Host’:’A’*750}, confirm=False).
The overflow corrupts adjoining heap metadata, probably enabling extra subtle exploitation methods.
CVE-2025-40598: Cross-site Scripting Flaw
The third vulnerability represents a simple mirrored cross-site scripting flaw within the radiusChallengeLogin CGI endpoint.
The state parameter displays consumer enter instantly into HTTP responses with out sanitization or encoding.
Exploitation requires minimal sophistication:
CVETitleCVSS 3.1 ScoreSeverityCVE-2025-40596Pre-Authentication Stack-Primarily based Buffer Overflow7.3 HighCVE-2025-40597Pre-Authentication Heap-Primarily based Buffer Overflow7.5HighCVE-2025-40598Reflected Cross-Web site Scripting (XSS)6.1Medium
Notably, the SMA100’s Net Utility Firewall options seem disabled on administration interfaces, permitting even primary XSS payloads to execute efficiently.
These vulnerabilities underscore persistent safety challenges in community equipment growth, the place basic programming errors proceed enabling pre-authentication assaults in opposition to crucial infrastructure parts.
SonicWall has revealed an advisory addressing these points by its Product Safety Incident Response Crew.
Organizations counting on SonicWall SMA100 sequence units ought to instantly apply out there patches and think about implementing further network-level protections till full remediation is achieved.
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