Buffer Overflow in Local Command-Line Utilities |
Attack Pattern ID: 9 (Detailed Attack Pattern Completeness: Complete) | Typical Severity: High | Status: Draft |
Summary
This attack targets command-line utilities available in a number of shells. An attacker can leverage a vulnerability found in a command-line utility to escalate privilege to root.
Attack Execution Flow
Attacker identifies command utilities exposed by the target host.
On the probing stage, the attacker interacts with the command utility and observes the results of its input. The attacker's goal is to uncover a buffer oveflow in the command utility. For instance the attacker may find that input data are not properly validated.
The attacker finds a buffer overflow vulnerability in the command utility and tries to exploit it. He crafts malicious code and injects it using the command utility. The attacker can at worst execute remote code on the target host.
The target host exposes a command-line utility to the user.
The command-line utility exposed by the target host has a buffer overflow vulnerability that can be exploited.
Description
A buffer overflow in the HPUX passwd command allows local users to gain root privileges via a command-line option.
A buffer overflow in Solaris's getopt command (found in libc) allows local users to gain root privileges via a long argv[0].
Skill or Knowledge Level: Low
An attacker can simply overflow a buffer by inserting a long string into an attacker-modifiable injection vector. The result can be a DoS.
High : Exploiting a buffer overflow to inject malicious code into the stack of a software system or even the heap can require a higher skill level.
The attacker can probe for services available on the target host. Many services may expose a command utility. For instance Telnet is a service which can be invoked through a command shell.
Carefully review the service's implementation before making it available to user. For instance you can use manual or automated code review to uncover vulnerabilities such as buffer overflow.
Use a language or compiler that performs automatic bounds checking.
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Compiler-based canary mechanisms such as StackGuard, ProPolice and the Microsoft Visual Studio /GS flag. Unless this provides automatic bounds checking, it is not a complete solution.
Operational: Use OS-level preventative functionality. Not a complete solution.
Apply the latest patches to your user exposed services. This may not be a complete solution, specially against zero day attack.
Do not unnecessarily expose services.
- Privilege Escalation
- Run Arbitrary Code
- Data Modification
- Denial of Service
- Information Leakage
When the function returns control to the main program, it jumps to the return address portion of the stack frame. Unfortunately that return address may have been overwritten by the overflowed buffer and the address may contain a call to a privileged command or to a malicious code.
CWE-ID | Weakness Name | Weakness Relationship Type |
---|---|---|
120 | Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') | Targeted |
118 | Improper Access of Indexable Resource ('Range Error') | Targeted |
119 | Failure to Constrain Operations within the Bounds of a Memory Buffer | Targeted |
74 | Failure to Sanitize Data into a Different Plane ('Injection') | Targeted |
20 | Improper Input Validation | Targeted |
680 | Integer Overflow to Buffer Overflow | Targeted |
733 | Compiler Optimization Removal or Modification of Security-critical Code | Secondary |
697 | Insufficient Comparison | Targeted |
Nature | Type | ID | Name | Description | View(s) this relationship pertains to![]() |
---|---|---|---|---|---|
ChildOf | ![]() | 10 | Buffer Overflow via Environment Variables | Mechanism of Attack1000 | |
ChildOf | ![]() | 100 | Overflow Buffers | Mechanism of Attack (primary)1000 | |
ParentOf | ![]() | 69 | Target Programs with Elevated Privileges | Mechanism of Attack1000 |
CWE - Buffer Errors
Submissions | ||||
---|---|---|---|---|
Submitter | Organization | Date | ||
G. Hoglund and G. McGraw. Exploiting Software: How to Break Code. Addison-Wesley, February 2004. | Cigital, Inc | 2007-03-01 |
Modifications | |||||
---|---|---|---|---|---|
Modifier | Organization | Date | Comments | ||
Eric Dalci | Cigital, Inc | 2007-02-13 | Fleshed out content to CAPEC schema from the original descriptions in "Exploiting Software" | ||
Sean Barnum | Cigital, Inc | 2007-03-05 | Review and revise | ||
Richard Struse | VOXEM, Inc | 2007-03-26 | Review and feedback leading to changes in Attack Execution Flow, Probing Techniques and Method of Attack | ||
Sean Barnum | Cigital, Inc | 2007-04-13 | Modified pattern content according to review and feedback |