Multiple RCE vulnerabilities in GNU Bash aka Shellshock
| Risk | Critical |
| Patch available | YES |
| Number of vulnerabilities | 6 |
| CVE-ID | CVE-2014-6271 CVE-2014-7169 CVE-2014-6277 CVE-2014-6278 CVE-2014-7186 CVE-2014-7187 |
| CWE-ID | CWE-77 CWE-119 CWE-193 |
| Exploitation vector | Network |
| Public exploit |
Vulnerability #1 is being exploited in the wild. Vulnerability #2 is being exploited in the wild. Vulnerability #3 is being exploited in the wild. Vulnerability #4 is being exploited in the wild. Vulnerability #5 is being exploited in the wild. Vulnerability #6 is being exploited in the wild. |
| Vulnerable software Subscribe |
Bash Universal components / Libraries / Scripting languages |
| Vendor | GNU |
Security Bulletin
This security bulletin contains information about 6 vulnerabilities.
1) Command injection
EUVDB-ID: #VU5295
Risk: Critical
CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]
CVE-ID: CVE-2014-6271
CWE-ID:
CWE-77 - Command injection
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary commands on the target system.
The vulnerability exists due to incorrect parsing of environment variables. A remote attacker can execute arbitrary code on the target system as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution.
Successful exploitation may allow an attacker to gain complete control over vulnerable system.
Exploitation example:
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
Note: this vulnerability was being actively exploited in the wild.
MitigationUpdate GNU Bash to version 4.3 bash43-027.
Vulnerable software versionsBash: 1.14.0 - 4.3
External linkshttp://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
Yes. This vulnerability is being exploited in the wild.
2) Command injection
EUVDB-ID: #VU5294
Risk: Critical
CVSSv3.1: 9.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]
CVE-ID: CVE-2014-7169
CWE-ID:
CWE-77 - Command injection
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary commands on the target system.
The weakness exists due to an incomplete fix related to malformed function definitions in the values of environment variables. By using multiple attack vectors (DHCP, HTTP, SIP, FTP, and SMTP) involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, a remote attacker can inject and execute arbitrary commands.This vulnerability exists due to incomplete fix for vulnerability #1 (CVE-2014-6271).
Exploitation example:
env X='() { (a)=>\' bash -c "echo date"; cat echo
Successful exploitation may allow an attacker to gain complete control over vulnerable system.
Note: this vulnerability was being actively exploited.
MitigationUpdate GNU Bash to version 4.3 bash43-027.
Vulnerable software versionsBash: 1.14.0 - 4.3
External linkshttp://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
Yes. This vulnerability is being exploited in the wild.
3) Memory corruption
EUVDB-ID: #VU5310
Risk: Critical
CVSSv3.1: 9.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]
CVE-ID: CVE-2014-6277
CWE-ID:
CWE-119 - Memory corruption
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to incorrect parsing of environment variables. A remote attacker can trigger memory corruption and execute arbitrary code on the target system as demonstrated by vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, scripts executed by unspecified DHCP clients, and other situations in which setting the environment occurs across a privilege boundary from Bash execution. The vulnerability was introduced by incorrect patching of vulnerabilities #1 (CVE-2014-6271) and #2 (CVE-2014-7169).
Successful exploitation results in arbitrary code execution on the vulnerable system.
Note: this vulnerability was being actively exploited in the wild.
Mitigation
Update GNU Bash to version 4.3 bash43-027.
Vulnerable software versionsBash: 1.14.0 - 4.3
External linkshttp://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.
4) Command injection
EUVDB-ID: #VU5322
Risk: Critical
CVSSv3.1: 9.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]
CVE-ID: CVE-2014-6278
CWE-ID:
CWE-77 - Command injection
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The weakness exists due to an incomplete fix related to the parsing of user scripts. By using attack vectors involving the ForceCommand feature in OpenSSH sshd, the mod_cgi and mod_cgid modules in the Apache HTTP Server, a remote attacker can execute arbitrary code with privileges of the current user. The vulnerability was introduced by incorrect patching of vulnerabilities #1 (CVE-2014-6271), #2 (CVE-2014-7169) and #3 (CVE-2014-6277)
Successful exploitation results in arbitrary code execution on the vulnerable system.
Note: this vulnerability was being actively exploited.
Mitigation
Update GNU Bash to version 4.3 bash43-027.
Vulnerable software versionsBash: 1.14.0 - 4.3
External linkshttp://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.
5) Memory corruption
EUVDB-ID: #VU5327
Risk: Critical
CVSSv3.1: 9.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]
CVE-ID: CVE-2014-7186
CWE-ID:
CWE-119 - Memory corruption
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The weakness exists due to out-of-bounds memory access while handling multiple "<<EOF" declarations. A remote attacker can trigger memory corruption and execute arbitrary code.
Exploitation example:
bash -c 'true <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF' || echo "CVE-2014-7186 vulnerable, redir_stack"
Successful exploitation results in arbitrary code execution on the vulnerable system.
Note: this vulnerability was being actively exploited.
Mitigation
Update GNU Bash to version 4.3 bash43-027.
Vulnerable software versionsBash: 1.14.0 - 4.3
External linkshttp://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.
6) Off-by-one error
EUVDB-ID: #VU5328
Risk: Critical
CVSSv3.1: 9.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]
CVE-ID: CVE-2014-7187
CWE-ID:
CWE-193 - Off-by-one Error
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The weakness exists due to off-by-one-error when handling deeply nested flow control constructs. A remote attacker can trigger memory corruption and execute arbitrary code with privileges of the current user.
Exploitation example:
(for x in {1..200} ; do echo "for x$x in ; do :"; done; for x in {1..200} ; do echo done ; done) | bash ||
echo "CVE-2014-7187 vulnerable, word_lineno"
Successful exploitation results in arbitrary code execution on the vulnerable system.
Note: this vulnerability was being actively exploited.
Mitigation
Update GNU Bash to version 4.3 bash43-027.
Vulnerable software versionsBash: 1.14.0 - 4.3
External linkshttp://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-027
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.
