Arch Linux Security Advisory ASA-201708-16 ========================================== Severity: Medium Date : 2017-08-22 CVE-ID : CVE-2017-1000099 CVE-2017-1000100 CVE-2017-1000101 Package : curl Type : information disclosure Remote : Yes Link : https://security.archlinux.org/AVG-370 Summary ======= The package curl before version 7.55-1 is vulnerable to information disclosure. Resolution ========== Upgrade to 7.55-1. # pacman -Syu "curl>=7.55-1" The problems have been fixed upstream in version 7.55. Workaround ========== None. Description =========== - CVE-2017-1000099 (information disclosure) An information disclosure issue has been found in curl < 7.55.0. When asking to get a file from a file:// URL, libcurl provides a feature that outputs meta-data about the file using HTTP-like headers. The code doing this would send the wrong buffer to the user (stdout or the application's provide callback), which could lead to other private data from the heap to get inadvertently displayed. The wrong buffer was an uninitialized memory area allocated on the heap and if it turned out to not contain any zero byte, it would continue and display the data following that buffer in memory. - CVE-2017-1000100 (information disclosure) An information disclosure issue has been found in curl < 7.55.0. When doing a TFTP transfer and curl/libcurl is given a URL that contains a very long file name (longer than about 515 bytes), the file name is truncated to fit within the buffer boundaries, but the buffer size is still wrongly updated to use the untruncated length. This too large value is then used in the sendto() call, making curl attempt to send more data than what is actually put into the buffer. The sendto() function will then read beyond the end of the heap based buffer. A malicious HTTP(S) server could redirect a vulnerable libcurl-using client to a crafted TFTP URL (if the client hasn't restricted which protocols it allows redirects to) and trick it to send private memory contents to a remote server over UDP. - CVE-2017-1000101 (information disclosure) A heap-based read buffer overflow has been found in curl < 7.55.0. In the globbing function that parses the numerical range, there was an omission that made curl read a byte beyond the end of the URL if given a carefully crafted, or just wrongly written, URL. The URL is stored in a heap based buffer, so it could then be made to wrongly read something else instead of crashing. An example of a URL that triggers the flaw would be http://ur%20[0-60000000000000000000. This flaw only affects the curl command line tool, not the libcurl library. Impact ====== An attacker is able to read sensitive information by asking curl to retrieve a maliciously crafted URL. References ========== https://curl.haxx.se/docs/adv_20170809C.html https://curl.haxx.se/CVE-2017-1000099.patch https://curl.haxx.se/docs/adv_20170809B.html https://curl.haxx.se/CVE-2017-1000100.patch https://curl.haxx.se/docs/adv_20170809A.html https://curl.haxx.se/CVE-2017-1000101.patch https://security.archlinux.org/CVE-2017-1000099 https://security.archlinux.org/CVE-2017-1000100 https://security.archlinux.org/CVE-2017-1000101