Recently, NSFOCUS monitored curl’s official security announcement, which fixed the SOCKS5 heap buffer overflow vulnerability (CVE-2023-38545) and cookie injection vulnerability (CVE-2023-38546). The details of the vulnerability have been made public. Affected users should upgrade curl as soon as possible.
SOCKS5 Heap Buffer Overflow Vulnerability (CVS 2023-38545)
When curl is required to pass the host name to the SOCKS5 agent for address resolution, if the host name exceeds 255 bytes, curl will experience a heap based buffer overflow. Due to the slow SOCKS5 grip, a local variable may generate incorrect values, resulting in curl not copying resolved addresses, but copying overly long host names to the destination buffer. This vulnerability affects both the command-line tool curl and the dependent library libcurl.
Cookie injection vulnerability (CVS 2023-38546)
Under specific conditions, attackers can insert Cookie into the program. This vulnerability is due to the use of curl_ easy_dupandle when copying “easy handles”, the Cookie enable state is copied, but the specific Cookies are not copied. This may cause the copied handle to load cookies from a file with the suffix ‘none’, and further leads to Cookie injection. This situation requires multiple conditions to be met, thus the vulnerability risk is lower and only affecting libcurl.
Scope of Impact
Note: Operating systems using libcurl and components derived from cURL and libcurl are also affected by the aforementioned vulnerabilities
At present, the official has released a new version to fix the above vulnerabilities. It is recommended that affected users update and upgrade in a timely manner to protect:
Temporary mitigation measures
1. Do not enable proxy in CURLPROXY_ SOCKS5_ HOSTNAME setting;
2. Do not set the proxy environment variable to socks5h://
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