Sneed-Reactivity/yara-Neo23x0/expl_cve_2021_26084_confluence_log.yar
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2024-07-25 12:43:35 -05:00

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rule LOG_EXPL_Confluence_RCE_CVE_2021_26084_Sep21 : LOG {
meta:
description = "Detects exploitation attempts against Confluence servers abusing a RCE reported as CVE-2021-26084"
author = "Florian Roth (Nextron Systems)"
reference = "https://github.com/httpvoid/writeups/blob/main/Confluence-RCE.md"
date = "2021-09-01"
score = 55
id = "bbf98ce4-d32b-541a-b727-bc35c9aaef53"
strings:
$xr1 = /isSafeExpression Unsafe clause found in \['[^\n]{1,64}\\u0027/ ascii wide
$xs1 = "[util.velocity.debug.DebugReferenceInsertionEventHandler] referenceInsert resolving reference [$!queryString]"
$xs2 = "userName: anonymous | action: createpage-entervariables ognl.ExpressionSyntaxException: Malformed OGNL expression: '\\' [ognl.TokenMgrError: Lexical error at line 1"
$sa1 = "GET /pages/doenterpagevariables.action"
$sb1 = "%5c%75%30%30%32%37"
$sb2 = "\\u0027"
$sc1 = " ERROR "
$sc2 = " | userName: anonymous | action: createpage-entervariables"
$re1 = /\[confluence\.plugins\.synchrony\.SynchronyContextProvider\] getContextMap (\n )?-- url: \/pages\/createpage-entervariables\.action/
condition:
1 of ($x*) or ( $sa1 and 1 of ($sb*) ) or (all of ($sc*) and $re1)
}