YARA · Signature Base (Florian Roth / Nextron)
SIGNATURE_BASE_APT_MAL_UNC4841_SEASPY_Jun23_1
Detects SEASPY malware used by UNC4841 in attacks against Barracuda ESG appliances exploiting CVE-2023-2868
- Author
- Florian Roth
- Date
- 2023-06-16
- Modified
- 2023-12-05
- Score / Quality
- 85 / 85
What this rule detects
Detects SEASPY malware used by UNC4841 in attacks against Barracuda ESG appliances exploiting CVE-2023-2868
It defines 9 patterns (6 text, 3 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule SIGNATURE_BASE_APT_MAL_UNC4841_SEASPY_Jun23_1 : CVE_2023_2868 FILE
{
meta:
= "Detects SEASPY malware used by UNC4841 in attacks against Barracuda ESG appliances exploiting CVE-2023-2868"
= "Florian Roth"
= "bcff58f8-87f6-5371-8b96-5d4c0f349000"
= "2023-06-16"
= "2023-12-05"
= "https://blog.talosintelligence.com/alchimist-offensive-framework/"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_barracuda_esg_unc4841_jun23.yar#L30-L55"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
= "3f26a13f023ad0dcd7f2aa4e7771bba74910ee227b4b36ff72edc5f07336f115"
= "c1dcb841fb872f0d5e661bfd90fca3075f5efc95b1f9dfff72fa318ed131e9d1"
= 85
= 85
= "CVE-2023-2868, FILE"
strings:
$sx1 = "usage: ./BarracudaMailService <Network-Interface>. e.g.: ./BarracudaMailService eth0" ascii fullword
$s1 = "fcntl.tmp.amd64." ascii
$s2 = "Child process id:%d" ascii fullword
$s3 = "[*]Success!" ascii fullword
$s4 = "NO port code" ascii
$s5 = "enter open tty shell" ascii
$op1 = { 48 89 c6 f3 a6 0f 84 f7 01 00 00 bf 6c 84 5f 00 b9 05 00 00 00 48 89 c6 f3 a6 0f 84 6a 01 00 00 }
$op2 = { f3 a6 0f 84 d2 00 00 00 48 89 de bf 51 5e 61 00 b9 05 00 00 00 f3 a6 74 21 48 89 de }
$op3 = { 72 de 45 89 f4 e9 b8 f4 ff ff 48 8b 73 08 45 85 e4 ba 49 3d 62 00 b8 44 81 62 00 48 0f 45 d0 }
condition:
uint16( 0 ) == 0x457f and filesize < 9000KB and 3 of them or 5 of them
}
Strings (9 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $sx1 | text | "usage: ./BarracudaMailService <Network-Interface>. e.g.: ./BarracudaMailService eth0" | ascii fullword |
| $s1 | text | "fcntl.tmp.amd64." | ascii |
| $s2 | text | "Child process id:%d" | ascii fullword |
| $s3 | text | "[*]Success!" | ascii fullword |
| $s4 | text | "NO port code" | ascii |
| $s5 | text | "enter open tty shell" | ascii |
| $op1 | hex | { 48 89 c6 f3 a6 0f 84 f7 01 00 00 bf 6c 84 5f 00 b9 05 00 00 00 48 89 c6 f3 a6 0f 84 6a 01 00 00 } | |
| $op2 | hex | { f3 a6 0f 84 d2 00 00 00 48 89 de bf 51 5e 61 00 b9 05 00 00 00 f3 a6 74 21 48 89 de } | |
| $op3 | hex | { 72 de 45 89 f4 e9 b8 f4 ff ff 48 8b 73 08 45 85 e4 ba 49 3d 62 00 b8 44 81 62 00 48 0f 45 d0 } |
Condition
uint16( 0 ) == 0x457f and filesize < 9000KB and 3 of them or 5 of themIn plain words (Heuristic)
- The file must be smaller than 9000KB (a cheap guard that skips large files).
- At least 3 patterns in the rule must match.
- At least 5 patterns in the rule must match.
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- 3f26a13f023ad0dcd7f2aa4e7771bba74910ee227b4b36ff72edc5f07336f115
Licence & attribution
Author: Florian Roth
Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a
Licence: Detection Rule License 1.1 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: bcff58f8-87f6-5371-8b96-5d4c0f349000
Tags:CVE_2023_2868FILE
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