CWE-290 使用欺骗进行的认证绕过

Authentication Bypass by Spoofing

结构: Simple

Abstraction: Base

状态: Incomplete

被利用可能性: unkown

基本描述

This attack-focused weakness is caused by improperly implemented authentication schemes that are subject to spoofing attacks.

相关缺陷

  • cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 1000 cwe_Ordinal: Primary

  • cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 1003 cwe_Ordinal: Primary

  • cwe_Nature: ChildOf cwe_CWE_ID: 287 cwe_View_ID: 699 cwe_Ordinal: Primary

常见的影响

范围 影响 注释
Access Control ['Bypass Protection Mechanism', 'Gain Privileges or Assume Identity'] This weakness can allow an attacker to access resources which are not otherwise accessible without proper authentication.

示例代码

例

The following code authenticates users.

bad Java

String sourceIP = request.getRemoteAddr();
if (sourceIP != null && sourceIP.equals(APPROVED_IP)) {
authenticated = true;
}

The authentication mechanism implemented relies on an IP address for source validation. If an attacker is able to spoof the IP, they may be able to bypass the authentication mechanism.

例

Both of these examples check if a request is from a trusted address before responding to the request.

bad C

sd = socket(AF_INET, SOCK_DGRAM, 0);
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = htonl(INADDR_ANY);
servr.sin_port = htons(1008);
bind(sd, (struct sockaddr ) & serv, sizeof(serv));

while (1) {
memset(msg, 0x0, MAX_MSG);
clilen = sizeof(cli);
if (inet_ntoa(cli.sin_addr)==getTrustedAddress()) {
n = recvfrom(sd, msg, MAX_MSG, 0, (struct sockaddr ) & cli, &clilen);
}
}

bad Java

while(true) {
DatagramPacket rp=new DatagramPacket(rData,rData.length);
outSock.receive(rp);
String in = new String(p.getData(),0, rp.getLength());
InetAddress clientIPAddress = rp.getAddress();
int port = rp.getPort();

if (isTrustedAddress(clientIPAddress) & secretKey.equals(in)) {
out = secret.getBytes();
DatagramPacket sp =new DatagramPacket(out,out.length, IPAddress, port); outSock.send(sp);
}
}

The code only verifies the address as stored in the request packet. An attacker can spoof this address, thus impersonating a trusted client

例

The following code samples use a DNS lookup in order to decide whether or not an inbound request is from a trusted host. If an attacker can poison the DNS cache, they can gain trusted status.

bad C

struct hostent hp;struct in_addr myaddr;
char tHost = "trustme.example.com";
myaddr.s_addr=inet_addr(ip_addr_string);

hp = gethostbyaddr((char *) &myaddr, sizeof(struct in_addr), AF_INET);
if (hp && !strncmp(hp->h_name, tHost, sizeof(tHost))) {
trusted = true;
} else {
trusted = false;
}

bad Java

String ip = request.getRemoteAddr();
InetAddress addr = InetAddress.getByName(ip);
if (addr.getCanonicalHostName().endsWith("trustme.com")) {
trusted = true;
}

bad C#

IPAddress hostIPAddress = IPAddress.Parse(RemoteIpAddress);
IPHostEntry hostInfo = Dns.GetHostByAddress(hostIPAddress);
if (hostInfo.HostName.EndsWith("trustme.com")) {
trusted = true;
}

IP addresses are more reliable than DNS names, but they can also be spoofed. Attackers can easily forge the source IP address of the packets they send, but response packets will return to the forged IP address. To see the response packets, the attacker has to sniff the traffic between the victim machine and the forged IP address. In order to accomplish the required sniffing, attackers typically attempt to locate themselves on the same subnet as the victim machine. Attackers may be able to circumvent this requirement by using source routing, but source routing is disabled across much of the Internet today. In summary, IP address verification can be a useful part of an authentication scheme, but it should not be the single factor required for authentication.

分析过的案例

标识 说明 链接

Notes

分类映射

映射的分类名 ImNode ID Fit Mapped Node Name
PLOVER Authentication bypass by spoofing

相关攻击模式

  • CAPEC-21
  • CAPEC-22
  • CAPEC-459
  • CAPEC-461
  • CAPEC-473
  • CAPEC-476
  • CAPEC-59
  • CAPEC-60
  • CAPEC-94

引用