Kingdom: Security Features
Software security is not security software. Here we're concerned with topics like authentication, access control, confidentiality, cryptography, and privilege management.
Access Control: Privilege Escalation
Abstract
The program may allow an unauthorized user to execute commands reserved for more privileged users.
Explanation
Normally authorization checks in an SAP application are done for the user executing the application (logged on user). However, it is possible to check authorization for a different user (other than the logged on user) programmatically in the following ways:
1. Statement
2. Function module
3. Function module
While such checks may be necessary at times, often they pose a security risk of privilege escalation. A malicious user with control over the input 'user id' against which authorization checks are done will be able to trick the system into providing access that is otherwise prohibited to the user by supplying a known super-user (like SAP* or DDIC, for example).
Even in cases where a user has no direct control over the 'user id' used for authorization checks, probing the authorization for a different user is considered a bad practice and has to be avoided. Logged on user (sy-uname) need not be explicitly specified when performing authorization checks. That is the default behavior - specifying it explicitly only opens door to exploitation where sy-uname may be manipulated before the check is actually executed. It is therefore a good idea to skip checking authorizations for a different user in general and explicitly specifying the logged on user in particular.
Example 1: The following code checks user authorizations before calling a transaction that can execute any ABAP program.
In this case, an otherwise unauthorized user will be able to start any ABAP program by supplying a known super-user (like SAP* or DDIC) to the variable v_user.
1. Statement
AUTHORITY-CHECK is used together with the addition FOR USER2. Function module
AUTHORITY_CHECK is invoked with the specified user3. Function module
SU_RAUTH_CHECK_FOR_USER is invoked with the specified userWhile such checks may be necessary at times, often they pose a security risk of privilege escalation. A malicious user with control over the input 'user id' against which authorization checks are done will be able to trick the system into providing access that is otherwise prohibited to the user by supplying a known super-user (like SAP* or DDIC, for example).
Even in cases where a user has no direct control over the 'user id' used for authorization checks, probing the authorization for a different user is considered a bad practice and has to be avoided. Logged on user (sy-uname) need not be explicitly specified when performing authorization checks. That is the default behavior - specifying it explicitly only opens door to exploitation where sy-uname may be manipulated before the check is actually executed. It is therefore a good idea to skip checking authorizations for a different user in general and explicitly specifying the logged on user in particular.
Example 1: The following code checks user authorizations before calling a transaction that can execute any ABAP program.
...
AUTHORITY-CHECK OBJECT 'S_TCODE' FOR USER v_user
ID 'TCD' FIELD 'SA38'.
IF sy-subrc = 0.
CALL TRANSACTION 'SA38'.
ELSE.
...
In this case, an otherwise unauthorized user will be able to start any ABAP program by supplying a known super-user (like SAP* or DDIC) to the variable v_user.
References
[1] SAP OSS Notes 20534, 179145, 136647 and related ones.
[2] Standards Mapping - Common Weakness Enumeration CWE ID 863
[3] Standards Mapping - Common Weakness Enumeration Top 25 2023 [24] CWE ID 863
[4] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-000213, CCI-001084, CCI-002165, CCI-002754
[5] Standards Mapping - FIPS200 AC
[6] Standards Mapping - General Data Protection Regulation (GDPR) Access Violation
[7] Standards Mapping - NIST Special Publication 800-53 Revision 4 AC-3 Access Enforcement (P1), CM-5 Access Restrictions for Change (P1), IA-2 Identification and Authentication (Organizational Users) (P1), IA-11 Re-Authentication (P0), SC-3 Security Function Isolation (P1), SI-10 Information Input Validation (P1)
[8] Standards Mapping - NIST Special Publication 800-53 Revision 5 AC-3 Access Enforcement, CM-5 Access Restrictions for Change, IA-2 Identification and Authentication (Organizational Users), SC-3 Security Function Isolation, SC-11 Trusted Path, SI-10 Information Input Validation
[9] Standards Mapping - OWASP API 2023 API3 Broken Object Property Level Authorization
[10] Standards Mapping - OWASP Application Security Verification Standard 4.0 4.1.3 General Access Control Design (L1 L2 L3), 4.1.5 General Access Control Design (L1 L2 L3), 4.2.1 Operation Level Access Control (L1 L2 L3), 13.1.4 Generic Web Service Security Verification Requirements (L2 L3)
[11] Standards Mapping - OWASP Mobile 2014 M5 Poor Authorization and Authentication
[12] Standards Mapping - OWASP Mobile 2024 M3 Insecure Authentication/Authorization
[13] Standards Mapping - OWASP Top 10 2004 A2 Broken Access Control
[14] Standards Mapping - OWASP Top 10 2007 A10 Failure to Restrict URL Access
[15] Standards Mapping - OWASP Top 10 2010 A8 Failure to Restrict URL Access
[16] Standards Mapping - OWASP Top 10 2013 A7 Missing Function Level Access Control
[17] Standards Mapping - OWASP Top 10 2017 A5 Broken Access Control
[18] Standards Mapping - OWASP Top 10 2021 A01 Broken Access Control
[19] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.2
[20] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.5.4
[21] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.8
[22] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.8
[23] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.8
[24] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.8
[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.8
[26] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4
[27] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 5.4 - Authentication and Access Control
[28] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 5.4 - Authentication and Access Control
[29] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 5.4 - Authentication and Access Control, Control Objective C.2.3 - Web Software Access Controls
[30] Standards Mapping - SANS Top 25 2009 Porous Defenses - CWE ID 285
[31] Standards Mapping - SANS Top 25 2010 Porous Defenses - CWE ID 285
[32] Standards Mapping - SANS Top 25 2011 Porous Defenses - CWE ID 862
[33] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3480.1 CAT II, APP3480.2 CAT II
[34] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3480.1 CAT I, APP3480.2 CAT II
[35] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3480.1 CAT I, APP3480.2 CAT II
[36] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3480.1 CAT I, APP3480.2 CAT II
[37] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3480.1 CAT I, APP3480.2 CAT II
[38] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3480.1 CAT I, APP3480.2 CAT II
[39] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3480.1 CAT I, APP3480.2 CAT II
[40] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[41] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[42] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[43] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[44] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[45] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[46] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[47] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[48] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[49] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[50] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[51] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[52] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[53] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-001410 CAT II, APSC-DV-001520 CAT II, APSC-DV-001530 CAT II, APSC-DV-001540 CAT I, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[54] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-001410 CAT II, APSC-DV-001520 CAT II, APSC-DV-001530 CAT II, APSC-DV-001540 CAT I, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[55] Standards Mapping - Web Application Security Consortium Version 2.00 Insufficient Authorization (WASC-02)
[56] Standards Mapping - Web Application Security Consortium 24 + 2 Insufficient Authorization
desc.structural.abap.access_control_privilege_escalation
Abstract
Access control mechanisms that rely on insufficiently validated user input might enable an attacker to gain unauthorized access to sensitive application resources and functionality.
Explanation
Privilege escalation issues occur when an attacker can bypass access control checks by submitting carefully crafted request parameter values. Applications that fail to sufficiently validate user supplied values that influence access control decisions expose themselves to authorization bypass threats. This can lead to attackers gaining access to sensitive resources or ability to remotely execute malicious arbitrary commands.
Example 1: The following code demonstrates authentication of administrative accounts
The example code uses the
To bypass the authorization checks, the attacker needs to ensure that
To force the value of
The attacker can fully bypass the authorization checks using the following values:
and send the result of
Example 1: The following code demonstrates authentication of administrative accounts
$admintest = 0;
if(isset($admin)) {
if(!IsSet($mainfile)) { include("mainfile.php3"); }
$admin = base64_decode($admin);
$admin = explode(":", $admin);
$aid = "$admin[0]";
$pwd = "$admin[1]";
dbconnect();
$result=mysql_query("select pwd from authors where aid='$aid'");
if(!$result) {
echo "Selection from database failed!";
exit;
} else {
list($pass)=mysql_fetch_row($result);
if($pass == $pwd) {
$admintest = 1;
}
}
}
The example code uses the
$admin value for access control checks. Any variables, either from cookies or forms (GET/POST) is automatically made global to the script by PHP. An attacker can manipulate the value of the admin variable by passing the desired value using a request parameter. If $pwd (an element of that "scrambled" $admin) does not match the value that corresponds to the fetched row, the false authentication ($admintest = 0) is returned, otherwise we'll be able to access any function in admin.php3.To bypass the authorization checks, the attacker needs to ensure that
$pass == $pwd. The $pass value returned from mysql_fetch_row() can be anything, or can be FALSE if there are no more rows. The attacker in this case can exploit the mismatch in the datatype to equalize $pwd (string-type) and $pass (logical-type). The expression "if($pass == $pwd)" only compares values, NOT the type. As a result, setting $pwd = "" (null) is EQUAL (though not identical) to the given FALSE value of $pass.To force the value of
$pass to FALSE, the attacker only needs to set $aid to a string value that does not exist in the database. This results in the mysql_query() call to return TRUE and the mysql_fetch_row() call to return FALSE.The attacker can fully bypass the authorization checks using the following values:
$aid = "blabla"; $pwd = "";
and send the result of
base64_encode("$aid:$pwd") in the admin request parameter.References
[1] Standards Mapping - Common Weakness Enumeration CWE ID 863
[2] Standards Mapping - Common Weakness Enumeration Top 25 2023 [24] CWE ID 863
[3] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-000213, CCI-001084, CCI-002165, CCI-002754
[4] Standards Mapping - FIPS200 AC
[5] Standards Mapping - General Data Protection Regulation (GDPR) Access Violation
[6] Standards Mapping - NIST Special Publication 800-53 Revision 4 AC-3 Access Enforcement (P1), CM-5 Access Restrictions for Change (P1), IA-2 Identification and Authentication (Organizational Users) (P1), IA-11 Re-Authentication (P0), SC-3 Security Function Isolation (P1), SI-10 Information Input Validation (P1)
[7] Standards Mapping - NIST Special Publication 800-53 Revision 5 AC-3 Access Enforcement, CM-5 Access Restrictions for Change, IA-2 Identification and Authentication (Organizational Users), SC-3 Security Function Isolation, SC-11 Trusted Path, SI-10 Information Input Validation
[8] Standards Mapping - OWASP API 2023 API3 Broken Object Property Level Authorization
[9] Standards Mapping - OWASP Application Security Verification Standard 4.0 4.1.3 General Access Control Design (L1 L2 L3), 4.1.5 General Access Control Design (L1 L2 L3), 4.2.1 Operation Level Access Control (L1 L2 L3), 13.1.4 Generic Web Service Security Verification Requirements (L2 L3)
[10] Standards Mapping - OWASP Mobile 2014 M5 Poor Authorization and Authentication
[11] Standards Mapping - OWASP Mobile 2024 M3 Insecure Authentication/Authorization
[12] Standards Mapping - OWASP Top 10 2004 A2 Broken Access Control
[13] Standards Mapping - OWASP Top 10 2007 A10 Failure to Restrict URL Access
[14] Standards Mapping - OWASP Top 10 2010 A8 Failure to Restrict URL Access
[15] Standards Mapping - OWASP Top 10 2013 A7 Missing Function Level Access Control
[16] Standards Mapping - OWASP Top 10 2017 A5 Broken Access Control
[17] Standards Mapping - OWASP Top 10 2021 A01 Broken Access Control
[18] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.2
[19] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.5.4
[20] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.8
[21] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.8
[22] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.8
[23] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.8
[24] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.8
[25] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4
[26] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 5.4 - Authentication and Access Control
[27] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 5.4 - Authentication and Access Control
[28] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 5.4 - Authentication and Access Control, Control Objective C.2.3 - Web Software Access Controls
[29] Standards Mapping - SANS Top 25 2009 Porous Defenses - CWE ID 285
[30] Standards Mapping - SANS Top 25 2010 Porous Defenses - CWE ID 285
[31] Standards Mapping - SANS Top 25 2011 Porous Defenses - CWE ID 862
[32] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3480.1 CAT II, APP3480.2 CAT II
[33] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3480.1 CAT I, APP3480.2 CAT II
[34] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3480.1 CAT I, APP3480.2 CAT II
[35] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3480.1 CAT I, APP3480.2 CAT II
[36] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3480.1 CAT I, APP3480.2 CAT II
[37] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3480.1 CAT I, APP3480.2 CAT II
[38] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3480.1 CAT I, APP3480.2 CAT II
[39] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[40] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[41] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[42] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[43] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[44] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[45] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[46] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[47] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[48] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[49] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[50] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[51] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[52] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-001410 CAT II, APSC-DV-001520 CAT II, APSC-DV-001530 CAT II, APSC-DV-001540 CAT I, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[53] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-000460 CAT I, APSC-DV-000470 CAT II, APSC-DV-001410 CAT II, APSC-DV-001520 CAT II, APSC-DV-001530 CAT II, APSC-DV-001540 CAT I, APSC-DV-002360 CAT II, APSC-DV-002560 CAT I
[54] Standards Mapping - Web Application Security Consortium Version 2.00 Insufficient Authorization (WASC-02)
[55] Standards Mapping - Web Application Security Consortium 24 + 2 Insufficient Authorization
desc.dynamic.php.access_control_privilege_escalation