Inside Cisco IOS Software Architecture
Inside Cisco IOS Software Architecture
A quantitative analysis of the insecurity of embedded network devices: results of a wide-area scan
Proceedings of the 26th Annual Computer Security Applications Conference
Defending embedded systems with software symbiotes
RAID'11 Proceedings of the 14th international conference on Recent Advances in Intrusion Detection
From prey to hunter: transforming legacy embedded devices into exploitation sensor grids
Proceedings of the 27th Annual Computer Security Applications Conference
Defending embedded systems with software symbiotes
RAID'11 Proceedings of the 14th international conference on Recent Advances in Intrusion Detection
| Hi-index | 0.00 |
IOS firmware diversity, the unintended consequence of a complex firmware compilation process, has historically made reliable exploitation of Cisco routers difficult. With approximately 300,000 unique IOS images in existence, a new class of version-agnostic shellcode is needed in order to make the large-scale exploitation of Cisco IOS possible. We show that such attacks are now feasible by demonstrating two different reliable shellcodes which will operate correctly over many Cisco hardware platforms and all known IOS versions. We propose a novel two-phase attack strategy against Cisco routers and the use of offline analysis of existing IOS images to defeat IOS firmware diversity. Furthermore, we discuss a new IOS rootkit which hijacks all interrupt service routines within the router and its ability to use intercept and modify process-switched packets just before they are scheduled for transmission. This ability allows the attacker to use the payload of innocuous packets, like ICMP, as a covert command and control channel. The same mechanism can be used to stealthily exfiltrate data out of the router, using response packets generated by the router itself as the vehicle. We present the implementation and quantitative reliability measurements by testing both shellcode algorithms against a large collection of IOS images. As our experimental results show, the techniques proposed in this paper can reliably inject command and control capabilities into arbitrary IOS images in a version-agnostic manner. We believe that the technique presented in this paper overcomes an important hurdle in the large-scale, reliable rootkit execution within Cisco IOS. Thus, effective host-based defense for such routers is imperative for maintaining the integrity of our global communication infrastructures.