Agent 1433: remote attack on Microsoft SQL Server
By Alexander Plakhov
Published: 2019-08-22 · Archived: 2026-04-05 13:48:11 UTC
All over the world companies large and small use Microsoft SQL Server for database management. Highly
popular yet insufficiently protected, this DBMS is a target of choice for hacking. One of the most common attack
on Microsoft SQL Server — the remote attack based on malicious jobs — has been around for a long time, but it
is still used to get access to workstations through less-than-strong administrator password.
Attempted attacks geography from January through July 2019
According to our statistics, the majority of such attacks fall on Vietnam (>16%), Russia (~12%), India (~7%),
China (~6%), Turkey and Brazil (5% each).
Attack description
https://securelist.com/malicious-tasks-in-ms-sql-server/92167/
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Microsoft SQL Server attacks are normally massive in nature and have no particular target: the attackers scan sub-networks in search of a server with a weak password. The attack begins with a remote check of whether the
system has MS SQL Server installed; next the intruders proceed to brute-force the account password to access the
system. In addition to password brute-forcing, they may also resort to authorization via a user account token,
authorized on a previously infected machine.
SQL Server authorization
As soon as penetration is accomplished, the attackers modify server configuration in order to access the command
line. That done, they can covertly make the malware secure in the target system using jobs they had created for the
SQL Server.
Examples of jobs
Job is a sequence of commands executed by SQL Server agent. It may comprise a broad range of actions,
including launching SQL transactions, command line applications, Microsoft ActiveX scripts, Integration Services
packages, Analysis Services commands and queries, as well as PowerShell scripts.
A job consists of steps, the code featured in each one being executed at certain intervals, allowing intruders to
deliver malicious files to the target computer again and again, should they be deleted.
Below are a few examples of malicious queries:
Installing a malware download job using the standard ftp.exe utility:
Downloading malware from a remote resource using JavaScript:
https://securelist.com/malicious-tasks-in-ms-sql-server/92167/
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Writing a malware file into the system followed by its execution:
We have analyzed the payloads delivered to the compromised machines via malicious jobs to learn that most of
them were cryptocurrency miners and remote access backdoors. The less common ones included passwords
capture and privilege escalation utilities. It should be mentioned, however, that the choice of payload depends on
the attackers’ goals and capabilities and is by no means limited to the mentioned options.
To protect your machines from malicious job attacks, we recommend using robust, brute-force-proof passwords
for your SQL Server accounts. It will also pay to check Agent SQL Server for third-party jobs.
Kaspersky Lab products return the following verdicts when detecting malware that installs malicious SQL Server
jobs:
Trojan.Multi.GenAutorunSQL.a
HEUR:Backdoor.Win32.RedDust.gen
HEUR:Backdoor.MSIL.RedDust.gen
And use proactive detection using the System Watcher component:
PDM:Trojan.Win32.GenAutorunSqlAgentJobRun.*
PDM:Trojan.Win32.Generic
PDM:Exploit.Win32.Generic
MD5
6754FA8C783A947414CE6591D6FA8540
91A12A4CF437589BA70B1687F5ACAD19
98DFA71C361283C4A1509C42F212FB0D
A3F0B689C7CCFDFAEADD7CBBF1CD92B6
E2A34F1D48CE4BE330F194E8AEFE9A55
https://securelist.com/malicious-tasks-in-ms-sql-server/92167/
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Source: https://securelist.com/malicious-tasks-in-ms-sql-server/92167/
https://securelist.com/malicious-tasks-in-ms-sql-server/92167/
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