Add JA3S fingerprint support #3850
Closed
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Generate JA3S fingerprints based on fields in the ServerHello record.
Add JA3S object to TLS JSON logger (extended log).
Add Ja3SGetHash() to return the content of the JA3S hash buffer from
the TLS session.
Example:
function init (args)
local needs = {}
needs["protocol"] = "tls"
return needs
end
function setup (args)
filename = SCLogPath() .. "/ja3s_hash.log"
file = assert(io.open(filename, "a"))
end
function log (args)
ja3s_hash = Ja3SGetHash()
if ja3s_hash == nil then
return
end
file:write(ja3s_hash .. "\n")
file:flush()
end
function deinit (args)
file:close()
end
In the example above, each JA3S hash is logged to a log file.
Add Ja3SGetString() to return the content of the JA3S string buffer from
the TLS session.
Example:
function init (args)
local needs = {}
needs["protocol"] = "tls"
return needs
end
function setup (args)
filename = SCLogPath() .. "/ja3s_string.log"
file = assert(io.open(filename, "a"))
end
function log (args)
ja3s_string = Ja3SGetString()
if ja3s_string == nil then
return
end
file:write(ja3s_string .. "\n")
file:flush()
end
function deinit (args)
file:close()
end
Match on JA3S hash using ja3s.hash keyword, e.g:
alert tls any any -> any any (msg:"ja3s.hash test";
ja3s.hash; content:"b26c652e0a402a24b5ca2a660e84f9d5"; sid:1;)
Match on JA3S string using ja3s.string keyword, e.g:
alert tls any any -> any any (msg:"ja3s.string test";
ja3s.string; content:"10-11-12"; sid:1;)
thus
commented
May 13, 2019
| { | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].name = "ja3s.hash"; | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].desc = "content modifier to match the JA3S sticky buffer"; | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].url = DOC_URL DOC_VERSION "/rules/ja3-keywords.html#ja3s.hash"; |
There was a problem hiding this comment.
This should probably be "#ja3s-hash" instead of "#ja3s.hash".
| { | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].name = "ja3s.string"; | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].desc = "content modifier to match the JA3S sticky buffer"; | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].url = DOC_URL DOC_VERSION "/rules/ja3-keywords.html#ja3s.string"; |
There was a problem hiding this comment.
This should probably be "#ja3s-string" instead of "#ja3s.string".
thus
commented
May 13, 2019
| void DetectTlsJa3SHashRegister(void) | ||
| { | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].name = "ja3s.hash"; | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].desc = "content modifier to match the JA3S sticky buffer"; |
There was a problem hiding this comment.
"match the JA3S hash sticky buffer" instead :)
| void DetectTlsJa3SStringRegister(void) | ||
| { | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].name = "ja3s.string"; | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].desc = "content modifier to match the JA3S sticky buffer"; |
There was a problem hiding this comment.
Should be "match the JA3S string sticky buffer".
thus
commented
May 14, 2019
| #endif | ||
| static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx, | ||
| const DetectEngineTransforms *transforms, | ||
| Flow *_f, const uint8_t _flow_flags, |
There was a problem hiding this comment.
Should remove the underscores from the variables here as well.
| #endif | ||
| static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx, | ||
| const DetectEngineTransforms *transforms, | ||
| Flow *_f, const uint8_t _flow_flags, |
| #ifdef UNITTESTS | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].RegisterTests = DetectTlsJa3SHashRegisterTests; | ||
| #endif | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_HASH].flags |= SIGMATCH_NOOPT; |
There was a problem hiding this comment.
add SIGMATCH_INFO_STICKY_BUFFER
| #ifdef UNITTESTS | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].RegisterTests = DetectTlsJa3SStringRegisterTests; | ||
| #endif | ||
| sigmatch_table[DETECT_AL_TLS_JA3S_STRING].flags |= SIGMATCH_NOOPT; |
|
Replaced by #3858 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This pull request implements JA3S fingerprints as implemented in the bro script in the JA3 github repo:
https://github.com/salesforce/ja3/blob/master/bro/ja3s.bro
Updates:
Redmine:
https://redmine.openinfosecfoundation.org/issues/2684