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Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.
14 distinct techniques documented for this family, organized by ATT&CK tactic.
In June 2007 several AV companies raised an alert due to a large-scale web-based attack being carried out with drive-by exploits. A malicious tag was injected into the homepages of many legitimate Italian and Russian websites. Attackers had injected an IFRAME to redirect visitors to a website running a multi-staged exploit kit, nowadays best known as ‘MPack’.
Attackers had injected an IFRAME to redirect visitors to a website running a multi-staged exploit kit, nowadays best known as ‘MPack’. The specific MPack installation used for this attack was designed to download several trojans from the remote server 81.95.146.150.
Trojan.Srizbi represents an important milestone in the evolution of malware utilizing kernel-mode techniques. It is the first complex full-kernel malware to have features such as file and registry hiding, bypassing of memory hooks, and low-level NDIS hooks with a private TCP/IP stack.
The Srizbi driver is installed by a dropper component that is packed with UPX and protected with a layer of scrambled code. This layer uses custom spaghetti code obfuscation with CALL/JMP mixed with junk opcodes... The dropper code makes API calls by using PUSH/RET sequences... making standard static analysis almost impossible.
We also found that Srizbi contains a generic driver removal routine based on CRC values... then the trojan unloads the driver with ZwUnloadDriver then deletes the launch point of the service by removing the related registry key and its sub keys.
However, it is possible to spot two principal decryption routines in the code: decryption with NOT BYTE decryption with BYTE XOR 0xB0... used to decrypt all text strings... and... the embedded driver.
Despite all the advanced features implemented for spam and networking, the major weakness of Srizbi is its hiding technique. The rootkit attempts to hide itself by placing the following kernel hooks: Inline hook: NtOpenKey, NtEnumerateKey \FileSystem\Ntfs driver: IRP_MJ_CREATE, IRP_MJ_DIRECTORY_CONTROL; These hooks effectively hide the malware’s driver file and registry keys.
To receive packets it uses the following hooks... For every packet received it checks whether it is a TCP packet, whether its destination IP equals the client's address, and whether the destination port is larger than 32,000. If all of these are true then it forwards the packet to its private stack.
To receive packets it uses the following hooks... For every packet received it checks whether it is a TCP packet, whether its destination IP equals the client's address, and whether the destination port is larger than 32,000. If all of these are true then it forwards the packet to its private stack.
The latter is utilized to implement a fully blown spam client with an HTTP-based command and control (C&C) infrastructure – all directly from ring 0... Once the trojan takes over NDIS networking, it contacts C&C servers on TCP port 4099 and retrieves spam instructions and configurations.
It is the first complex full-kernel malware to have features such as... low-level NDIS hooks with a private TCP/IP stack... Trojan.Srizbi uses its NDIS hooks and the original handler functions together with its own TCP/IP stack to send and receive packets.
2 indicators attributed across vendor reports, sandbox runs, and researcher write-ups. Full values are available in Mallory.
IPs, domains, and DNS infrastructure linked to this family.
1 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.