Azure WAF 403 响应

Question

我收到针对 API 的 PUT 请求的“403 ModSecurity Action”。获取和发布按预期工作。

我首先想到的是 WAF 可能会阻止特定的动词(即 PUT)，即“REQUEST-911-METHOD-ENFORCMENT”More info here

但随后网络团队设法找到了该请求的日志 -

TimeGenerated: 2018-05-04T09:55:42Z
    AzureDiagnostics    5/4/2018 10:55:42.000 AM    AzureDiagnostics    ApplicationGatewayFirewall  ApplicationGatewayFirewallLog   WAF-CPP-01  52.233.137.239  OWASP   3.0 200002  Blocked Global  Access denied with code 400 (phase 2). Match of "eq 0" against "REQBODY_ERROR" required.    JSON parsing error: parse error: invalid object key (must be a string)\x0a          cpp.api.cardiff.gov.uk  ApplicationGatewayRole_IN_0         

$table  AzureDiagnostics
TenantId    31c4d3f2-394f-4c06-833c-9d22912ec8ab
SourceSystem    Azure
TimeGenerated   2018-05-04T09:55:42Z
Type    AzureDiagnostics
ResourceId  /SUBSCRIPTIONS/ECA58BF3-DF5E-41E6-B113-BB96E1EBC768/RESOURCEGROUPS/RG-CPP-COREINFRASTRUCTURE/PROVIDERS/MICROSOFT.NETWORK/APPLICATIONGATEWAYS/WAF-CPP-01
OperationName   ApplicationGatewayFirewall
Category    ApplicationGatewayFirewallLog
Resource    WAF-CPP-01
ResourceGroup   RG-CPP-COREINFRASTRUCTURE
ResourceProvider    MICROSOFT.NETWORK
SubscriptionId  eca58bf3-df5e-41e6-b113-bb96e1ebc768
clientIp_s  52.233.137.239
ruleSetType_s   OWASP
ruleSetVersion_s    3.0
ruleId_s    200002
Message Mandatory rule. Cannot be disabled. Failed to parse request body.
action_s    Blocked
site_s  Global
details_message_s   Access denied with code 400 (phase 2). Match of "eq 0" against "REQBODY_ERROR" required.
details_data_s  JSON parsing error: parse error: invalid object key (must be a string)\x0a
hostname_s  cpp.api.cardiff.gov.uk
instanceId_s    ApplicationGatewayRole_IN_0
requestUri_s    /Notification/api/Notification/
ResourceType    APPLICATIONGATEWAYS
clientPort_d    0

    AzureDiagnostics    5/4/2018 10:55:42.000 AM    AzureDiagnostics    ApplicationGatewayAccess    ApplicationGatewayAccessLog WAF-CPP-01                                              ApplicationGatewayRole_IN_0 52.233.137.239  PUT 

$table  AzureDiagnostics
TenantId    31c4d3f2-394f-4c06-833c-9d22912ec8ab
SourceSystem    Azure
TimeGenerated   2018-05-04T09:55:42Z
Type    AzureDiagnostics
ResourceId  /SUBSCRIPTIONS/ECA58BF3-DF5E-41E6-B113-BB96E1EBC768/RESOURCEGROUPS/RG-CPP-COREINFRASTRUCTURE/PROVIDERS/MICROSOFT.NETWORK/APPLICATIONGATEWAYS/WAF-CPP-01
OperationName   ApplicationGatewayAccess
Category    ApplicationGatewayAccessLog
Resource    WAF-CPP-01
ResourceGroup   RG-CPP-COREINFRASTRUCTURE
ResourceProvider    MICROSOFT.NETWORK
SubscriptionId  eca58bf3-df5e-41e6-b113-bb96e1ebc768
instanceId_s    ApplicationGatewayRole_IN_0
clientIP_s  52.233.137.239
httpMethod_s    PUT
requestUri_s    /Notification/api/Notification/
requestQuery_s  -
userAgent_s PostmanRuntime/7.1.1
httpVersion_s   HTTP/1.1
sslEnabled_s    on
host_s  cpp.api.cardiff.gov.uk
ResourceType    APPLICATIONGATEWAYS
clientPort_d    1,025
httpStatus_d    400
receivedBytes_d 1,360
sentBytes_d 185
timeTaken_d 56

该错误提到请求正文存在错误并且 JSON 不正确。但我的结局似乎一切都很好:/

我已经通过 swagger 和 postman 进行了测试。

Answer 1

我们的 WAF 刚刚遇到了这个问题。问题不在于 JSON 格式错误，而在于它太大。我一直无法找到构成大型 JSON 有效负载的确切数字，但如果请求的内容长度超过大约 120-150kb，就会发生这种情况。