On November 5, local time, Squid officially released a security bulletin to fix multiple vulnerabilities, including a high-risk buffer overflow vulnerability that could lead to code execution (CVE-2019-12526), an information disclosure vulnerability (CVE-2019-18679) And HTTP request splitting problem (CVE-2019-18678).
Squid is a popular open source Internet proxy and web caching application. It can be used to reduce bandwidth usage and demand on web servers, filter network traffic, and accelerate web access by caching common resources locally. Squid supports a variety of network protocols, including HTTP, FTP, and Gopher. Squid supports proxy forwarding. Clients on the internal network connect to servers on the external network through Squid. Clients on the reverse proxy external network connect to servers on the internal network through Squid.
CVE-2019-12526: This vulnerability allows a remote attacker to write large amounts of arbitrary data to the heap due to incorrect buffer management, which may result in arbitrary code execution. On systems with memory access protection, the Squid process may be terminated abnormally, causing a denial of service to all clients that use the proxy.
CVE-2019-18679: Due to incorrect data management, Squid may leak information when processing HTTP digest authentication. The leaked information will weaken ASLR protection and may help attackers to implement remote code execution attacks.
CVE-2019-18678: Squid is prone to HTTP request splitting due to incorrect message parsing, with relatively low risk and impact.
Scope of Impact
- Squid 3.0 <= 3.5.28
- Squid 4.x <= 4.8
- Squid = 4.9
The user can use the command squid –v to view the currently installed version.
There may be a risk if the current version is within the affected range.
The above vulnerability has been fixed in the latest version, and affected users should upgrade to Squid 4.9 as soon as possible.
Official link: http://www.squid-cache.org/Versions/
The installation command is as follows:
tar -zxvf squid-4.9.tar.gz
make && make install
The screenshot of the successful installation is as follows:
Other Protective Measures
If the relevant users are temporarily unable to upgrade, the following measures can also be used to protect the corresponding vulnerabilities.
- The patch corresponding to the installation vulnerability
|Patch download link
Note: If you are using a pre-packaged version of Squid, please contact the package vendor for confirmation.
- Take protective measures against the vulnerability
Reject urn: protocol URI that is represented by all clients
acl URN proto URN
http_access deny URN
(1) Remove the “auth_param digest …” setting from the configuration file squid.conf.
(2) Add the parameter –disable-auth-basic when compiling Squid
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