27 lines
946 B
Text
27 lines
946 B
Text
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rule EXPL_Zoho_RCE_Fix_Lines_Dec21_1 {
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meta:
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description = "Detects lines in log lines of Zoho products that indicate RCE fixes (silent removal of evidence)"
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author = "Florian Roth (Nextron Systems)"
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reference = "https://twitter.com/cyb3rops/status/1467784104930385923"
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date = "2021-12-06"
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score = 65
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id = "633287e3-a377-5b3c-8520-a7790168eff5"
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strings:
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// we look for the RCE Fixes
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$s1 = "RCEF="
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// we try to find a line which states that the attack is active (compromised host)
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$sa1 = "\"attackStatus\"\\:\"active\""
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$sa2 = "\"attackStatus\":\"active\""
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// we try to find a line in which the RCE fix deleted a file (compromised host)
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$sd1 = "deletedCount"
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$sd_fp1 = "\"deletedCount\"\\:0"
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$sd_fp2 = "\"deletedCount\":0"
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condition:
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filesize < 6MB and $s1 and (
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1 of ($sa*) or
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( $sd1 and not 1 of ($sd_fp*) )
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)
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}
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