Several security issues were fixed in the GNU C library.
It was discovered that the GNU C library did not properly handle all of the possible return values from the kernel getcwd(2) syscall. A local attacker could potentially exploit this to execute arbitrary code in setuid programs and gain administrative privileges. (CVE-2018-1000001)
17 January 2018
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in the GNU C library.
It was discovered that the GNU C library did not properly handle all of the possible return values from the kernel getcwd(2) syscall. A local attacker could potentially exploit this to execute arbitrary code in setuid programs and gain administrative privileges. (CVE-2018-1000001)
A memory leak was discovered in the _dl_init_paths() function in the GNU C library dynamic loader. A local attacker could potentially exploit this with a specially crafted value in the LD_HWCAP_MASK environment variable, in combination with CVE-2017-1000409 and another vulnerability on a system with hardlink protections disabled, in order to gain administrative privileges. (CVE-2017-1000408)
A heap-based buffer overflow was discovered in the _dl_init_paths() function in the GNU C library dynamic loader. A local attacker could potentially exploit this with a specially crafted value in the LD_LIBRARY_PATH environment variable, in combination with CVE-2017-1000408 and another vulnerability on a system with hardlink protections disabled, in order to gain administrative privileges. (CVE-2017-1000409)
An off-by-one error leading to a heap-based buffer overflow was discovered in the GNU C library glob() implementation. An attacker could potentially exploit this to cause a denial of service or execute arbitrary code via a maliciously crafted pattern. (CVE-2017-15670)
A heap-based buffer overflow was discovered during unescaping of user names with the ~ operator in the GNU C library glob() implementation. An attacker could potentially exploit this to cause a denial of service or execute arbitrary code via a maliciously crafted pattern. (CVE-2017-15804)
It was discovered that the GNU C library dynamic loader mishandles RPATH and RUNPATH containing $ORIGIN for privileged (setuid or AT_SECURE) programs. A local attacker could potentially exploit this by providing a specially crafted library in the current working directory in order to gain administrative privileges. (CVE-2017-16997)
It was discovered that the GNU C library malloc() implementation could return a memory block that is too small if an attempt is made to allocate an object whose size is close to SIZE_MAX, resulting in a heap-based overflow. An attacker could potentially exploit this to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 17.10. (CVE-2017-17426)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.