Vulnerabilities > CVE-2021-34718 - Argument Injection or Modification vulnerability in Cisco IOS XR

An attacker attempts to invoke all common switches and options in the target application for the purpose of discovering weaknesses in the target. For example, in some applications, adding a --debug switch causes debugging information to be displayed, which can sometimes reveal sensitive processing or configuration information to an attacker. This attack differs from other forms of API abuse in that the attacker is blindly attempting to invoke options in the hope that one of them will work rather than specifically targeting a known option. Nonetheless, even if the attacker is familiar with the published options of a targeted application this attack method may still be fruitful as it might discover unpublicized functionality.

This type of attack involves an attacker leveraging meta-characters in email headers to inject improper behavior into email programs. Email software has become increasingly sophisticated and feature-rich. In addition, email applications are ubiquitous and connected directly to the Web making them ideal targets to launch and propagate attacks. As the user demand for new functionality in email applications grows, they become more like browsers with complex rendering and plug in routines. As more email functionality is included and abstracted from the user, this creates opportunities for attackers. Virtually all email applications do not list email header information by default, however the email header contains valuable attacker vectors for the attacker to exploit particularly if the behavior of the email client application is known. Meta-characters are hidden from the user, but can contain scripts, enumerations, probes, and other attacks against the user's system.

An attacker overrides or adds HTTP GET/POST parameters by injecting query string delimiters. Via HPP it may be possible to override existing hardcoded HTTP parameters, modify the application behaviors, access and, potentially exploit, uncontrollable variables, and bypass input validation checkpoints and WAF rules.

In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.