CVE-2018-1120

A flaw was found affecting the Linux kernel before version 4.17. By mmap()ing a FUSE-backed file onto a processs memory containing command line arguments (or environment strings), an attacker can cause utilities from psutils or procps (such as ps, w) or any other program which makes a read() call to the /proc//cmdline (or /proc//environ) files to block indefinitely (denial of service) or for some controlled time (as a synchronization primitive for other attacks).

Weakness

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Software

Potential Mitigations

• Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
• D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
• Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
• Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
• For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/92.html

References

• http://seclists.org/oss-sec/2018/q2/122
• http://www.securityfocus.com/bid/104229
• https://access.redhat.com/errata/RHSA-2018:2948
• https://access.redhat.com/errata/RHSA-2018:3083
• https://access.redhat.com/errata/RHSA-2018:3096
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1120
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7f7ccc2ccc2e70c6054685f5e3522efa81556830
• https://lists.debian.org/debian-lts-announce/2018/07/msg00020.html
• https://security.gentoo.org/glsa/201805-14
• https://usn.ubuntu.com/3752-1/
• https://usn.ubuntu.com/3752-2/
• https://usn.ubuntu.com/3752-3/
• https://usn.ubuntu.com/3910-1/
• https://usn.ubuntu.com/3910-2/
• https://www.exploit-db.com/exploits/44806/
• http://seclists.org/oss-sec/2018/q2/122
• http://www.securityfocus.com/bid/104229
• https://access.redhat.com/errata/RHSA-2018:2948
• https://access.redhat.com/errata/RHSA-2018:3083
• https://access.redhat.com/errata/RHSA-2018:3096
• https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-1120
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7f7ccc2ccc2e70c6054685f5e3522efa81556830
• https://lists.debian.org/debian-lts-announce/2018/07/msg00020.html
• https://security.gentoo.org/glsa/201805-14
• https://usn.ubuntu.com/3752-1/
• https://usn.ubuntu.com/3752-2/
• https://usn.ubuntu.com/3752-3/
• https://usn.ubuntu.com/3910-1/
• https://usn.ubuntu.com/3910-2/
• https://www.exploit-db.com/exploits/44806/