Update (May 14): Mandiant has observed multiple actors cite a May
13 announcement that appeared to be shared with DARKSIDE RaaS
affiliates by the operators of the service. This announcement stated
that they lost access to their infrastructure, including their blog,
payment, and CDN servers, and would be closing their service.
Decrypters would also be provided for companies who have not paid,
possibly to their affiliates to distribute. The post cited law
enforcement pressure and pressure from the United States for this
decision. We have not independently validated these claims and there
is some speculation by other actors that this could be an exit scam.
Since initially surfacing in August 2020, the creators of DARKSIDE
ransomware and their affiliates have launched a global crime spree
affecting organizations in more than 15 countries and multiple
industry verticals. Like many of their peers, these actors conduct
multifaceted extortion where data is both exfiltrated and encrypted in
place, allowing them to demand payment for unlocking and the
non-release of stolen data to exert more pressure on victims.
The origins of these incidents are not monolithic. DARKSIDE
ransomware operates as a ransomware-as-a-service (RaaS) wherein profit
is shared between its owners and partners, or affiliates, who provide
access to organizations and deploy the ransomware. Mandiant currently
tracks multiple threat clusters that have deployed this ransomware,
which is consistent with multiple affiliates using DARKSIDE. These
clusters demonstrated varying levels of technical sophistication
throughout intrusions. While the threat actors commonly relied on
commercially available and legitimate tools to facilitate various
stages of their operations, at least one of the threat clusters also
employed a now patched zero-day vulnerability.
Reporting on DARKSIDE has been available in advance of this blog
post to users of
Advantage Free, a no-cost version of our threat intelligence platform.
Mandiant has identified multiple DARKSIDE victims through our
incident response engagements and from reports on the DARKSIDE blog.
Most of the victim organizations were based in the United States and
span across multiple sectors, including financial services, legal,
manufacturing, professional services, retail, and technology. The
number of publicly named victims on the DARKSIDE blog has increased
overall since August 2020, with the exception of a significant dip in
the number of victims named during January 2021 (Figure 1). It is
plausible that the decline in January was due to threat actors using
DARKSIDE taking a break during the holiday season. The overall growth
in the number of victims demonstrates the increasing use of the
DARKSIDE ransomware by multiple affiliates.
Figure 1: Known DARKSIDE victims (August
2020 to April 2021)
Beginning in November 2020, the Russian-speaking actor
"darksupp" advertised DARKSIDE RaaS on the Russian-language
forums exploit.in and xss.is. In April 2021, darksupp posted an update
for the "Darkside 2.0" RaaS that included several new
features and a description of the types of partners and services they
were currently seeking (Table 1). Affiliates retain a percentage of
the ransom fee from each victim. Based on forum advertisements, the
RaaS operators take 25% for ransom fees less than $500,000, but this
decreases to 10 percent for ransom fees greater than $5 million.
In addition to providing builds of DARKSIDE ransomware, the
operators of this service also maintain a blog accessible via TOR. The
actors use this site to publicize victims in an attempt to
pressure these organizations into paying for the non-release of stolen
data. A recent update to their underground forum advertisement also
indicates that actors may attempt to DDoS victim organizations. The
actor darksupp has stated that affiliates are prohibited from
targeting hospitals, schools, universities, non-profit organizations,
and public sector entities. This may be an effort by the actor(s) to
deter law enforcement action, since targeting of these sectors may
invite additional scrutiny. Affiliates are also prohibited from
targeting organizations in Commonwealth of Independent States (CIS) nations.
|
|
|
Nov. 10, 2020 (V1)
| Ability to generate builds for both |
|
Encrypts files using Salsa20 encryption along | ||
Access to an administrative panel via TOR that | ||
The admin panel includes a Blog section that | ||
April 14, 2021 (V2.0)
| Automated test decryption. The process |
|
Available DDoS of targets (Layer 3, Layer | ||
Sought a partner to provide network accesses to |
Table 1: Notable features and updates listed on
DARKSIDE advertisement thread (exploit.in)
DARKSIDE Affiliates
DARKSIDE RaaS affiliates are required to pass an interview after
which they are provided access to an administration panel (Figure 2).
Within this panel, affiliates can perform various actions such as
creating a ransomware build, specifying content for the DARKSIDE blog,
managing victims, and contacting support. Mandiant has identified at
least five Russian-speaking actors who may currently, or have
previously, been DARKSIDE affiliates. Relevant advertisements
associated with a portion of these threat actors have been aimed at
finding either initial access providers or actors capable of deploying
ransomware on accesses already obtained. Some actors claiming to use
DARKSIDE have also allegedly partnered with other RaaS affiliate
programs, including BABUK and SODINOKIBI (aka REvil). For more
information on these threat actors, please see
Figure 2: DARKSIDE affiliate panel
Mandiant currently tracks five clusters of threat activity that have
involved the deployment of DARKSIDE. For more information on
uncategorized threats, refer to our post, "
Attribution: How Mandiant Tracks Uncategorized Threat
Actors." These clusters may represent different affiliates of
the DARKSIDE RaaS platform. Throughout observed incidents, the threat
actor commonly relied on various publicly available and legitimate
tools that are commonly used to facilitate various stages of the
attack lifecycle in post-exploitation ransomware attacks (Figure 3).
Additional details on three of these UNC groups are included below.
Figure 3: TTPs seen throughout DARKSIDE ransomware engagements
UNC2628
UNC2628 has been active since at least February 2021. Their
intrusions progress relatively quickly with the threat actor typically
deploying ransomware in two to three days. We have some evidence that
suggests UNC2628 has partnered with other RaaS including SODINOKIBI
(REvil) and NETWALKER.
UNC2659
UNC2659 has been active since at least January 2021. We have
observed the threat actor move through the whole attack lifecycle in
under 10 days. UNC2659 is notable given their use of an exploit in the
SonicWall SMA100 SSL VPN product, which has since been
by SonicWall. The threat actor appeared to download several tools used
for various phases of the attack lifecycle directly from those tools’
legitimate public websites.
UNC2465
UNC2465 activity dates back to at least April 2019 and is
characterized by their use of similar TTPs to distribute the
PowerShell-based .NET backdoor SMOKEDHAM in victim environments. In
one case where DARKSIDE was deployed, there were months-long gaps,
with only intermittent activity between the time of initial compromise
to ransomware deployment. In some cases, this could indicate that
initial access was provided by a separate actor.
We believe that threat actors have become more proficient at
conducting multifaceted extortion operations and that this success has
directly contributed to the rapid increase in the number of
high-impact ransomware incidents over the past few years. Ransomware
operators have incorporated additional extortion tactics designed to
increase the likelihood that victims will acquiesce to paying the
ransom prices. As one example, in late April 2021, the DARKSIDE
operators released a press release stating that they were targeting
organizations listed on the NASDAQ and other stock markets. They
indicated that they would be willing to give stock traders information
about upcoming leaks in order to allow them potential profits due to
stock price drops after an announced breach. In another notable
example, an attacker was able to obtain the victim's cyber insurance
policy and leveraged this information during the ransom negotiation
process refusing to lower the ransom amount given their knowledge of
the policy limits. This reinforces that during the post-exploitation
phase of ransomware incidents, threat actors can engage in internal
reconnaissance and obtain data to increase their negotiating power. We
expect that the extortion tactics that threat actors use to pressure
victims will continue to evolve throughout 2021.
Based on the evidence that DARKSIDE ransomware is distributed by
multiple actors, we anticipate that the TTPs used throughout incidents
associated with this ransomware will continue to vary somewhat. For
more comprehensive recommendations for addressing ransomware, please
refer to our blog post: "
Protection and Containment Strategies: Practical Guidance for
Endpoint Protection, Hardening, and Containment" and the
linked
Beyond the comparatively small number of people who are listed as
authors on this report are hundreds of consultants, analysts and
reverse-engineers who tirelessly put in the work needed to respond to
intrusions at breakneck pace and still maintain unbelievably high
analytical standards. This larger group has set the foundation for all
of our work, but a smaller group of people contributed more directly
to producing this report and we would like to thank them by name. We
would like to specifically thank Bryce Abdo and Matthew Dunwoody from
our Advanced Practices team and Jay Smith from FLARE, all of whom
provided analytical support and technical review. Notable support was
also provided by Ioana Teaca, and Muhammadumer Khan.
DARKSIDE is a ransomware written in C that may be configured to
encrypt files on fixed and removable disks as well as network shares.
DARKSIDE RaaS affiliates are given access to an administration panel
on which they create builds for specific victims. The panel allows
some degree of customization for each ransomware build such as
choosing the encryption mode and whether local disks and network
shares should be encrypted (Figures 4). The following malware analysis
is based on the file MD5: 1a700f845849e573ab3148daef1a3b0b. A more
recently analyzed DARKSIDE sample had the following notable differences:
Figure 4: DARKSIDE build configuration
options appearing in the administration panel
Persistence Mechanism
Early versions of the malware did not contain a persistence
mechanism. An external tool or installer was required if the attacker
desired persistence. A DARKSIDE version observed in May 2021 implement
a persistence mechanism through which the malware creates and launches
itself as a service with a service name and description named using
eight pseudo-randomly defined lowercase hexadecimal characters (e.g.,
".e98fc8f7") that are also appended by the malware to
various other artifacts it created. This string of characters is
referenced as <ransom_ext>. :
Service Name: <ransom_ext>
Description: <ransom_ext>
Created Files
%CD%\LOG<ransom_ext>.TXT
README<ransom_ext>.TXT
<original_filename_plus_ext><ransom_ext>
May
version: %PROGRAMDATA%\<ransom_ext>.ico
Registry Artifacts
The DARKSIDE version observed in May sets the following registry key:
HKCR\<ransom_ext>\DefaultIcon\<ransom_ext>\DefaultIcon=%PROGRAMDATA%\<ransom_ext>.ico
Configuration
The malware initializes a 0x100-byte keystream used to decrypt
strings and configuration data. Strings are decrypted as needed and
overwritten with NULL bytes after use. The malware's configuration
size is 0xBE9 bytes. A portion of the decrypted configuration is shown
in Figure 5.
| 00000000 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000060 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000070 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000080 95 AA A8 7C 2B 6A D5 12 0E 73 B3 7D BD 16 25 62 •ª¨|+jÕ..s³}½.%b 00000090 A4 A8 BF 19 73 F7 E0 BC DF 02 A8 94 32 CF 0C C0 ¤¨¿.s÷à¼ß.¨"2Ï.À 000000A0 C5 83 0F 14 66 02 87 EE FD 29 96 DF 02 05 C1 12 Ń..f.‡îý)–ß..Á. 000000B0 3E 43 A7 59 E1 F0 C4 5D AE E1 20 2E 77 D9 CA 3C >C§YáðÄ]®á .wÙÊ< 000000C0 AD C6 BC 84 75 1C E7 0B F0 30 2A 51 13 7A B2 66 .Ƽ„u.ç.ð0*Q.z²f 000000D0 44 73 79 E1 E4 69 C3 CA 1B C1 76 63 65 95 EA CA DsyáäiÃÊ.Ávce•êÊ 000000E0 F6 10 68 0D CE 36 61 F9 57 B9 19 50 31 D4 E1 70 ö.h.Î6aùW¹.P1Ôáp 000000F0 EC 7B 33 1E 4F 17 E1 80 1D BC CF 8C D8 C5 66 41 ì{3.O.á€.¼ÏŒØÅfA 00000100 E5 0A 00 00 02 6E 01 02 15 03 43 01 8E 24 0E 72 å....n....C.Ž$.r <cut> |
Figure 5: Partial decrypted configuration
The sample's 0x80-byte RSA public key blob begins at offset 0x80.
The DWORD value at offset 0x100 is multiplied by 64 and an amount of
memory equivalent to the result is allocated. The remaining bytes,
which start at offset 0x104, are aPLib-decompressed into the allocated
buffer. The decompressed bytes include the ransom note and other
elements of the malware's configuration described as follows (e.g.,
processes to terminate, files to ignore). The first 0x60 bytes of the
decompressed configuration are shown in Figure 6.
| 00000000 02 01 01 01 00 01 01 00 01 01 01 01 01 01 01 01 ................ 00000010 01 01 01 01 01 01 24 00 72 00 65 00 63 00 79 00 ......$.r.e.c.y. 00000020 63 00 6C 00 65 00 2E 00 62 00 69 00 6E 00 00 00 c.l.e...b.i.n... 00000030 63 00 6F 00 6E 00 66 00 69 00 67 00 2E 00 6D 00 c.o.n.f.i.g...m. 00000040 73 00 69 00 00 00 24 00 77 00 69 00 6E 00 64 00 s.i...$.w.i.n.d. 00000050 6F 00 77 00 73 00 2E 00 7E 00 62 00 74 00 00 00 o.w.s...~.b.t... <cut> |
Figure 6: Partial decompressed configuration
The first byte from Figure 6 indicates the encryption mode. This
sample is configured to encrypt using FAST mode. Supported values are
as follows:
The individual bytes from offset 0x02 to offset 0x15 in Figure 6 are
Boolean values that dictate the malware's behavior. The malware takes
the actions listed in Table 2 based on these values. Table 2 also
identifies features that are enabled or disabled for the current sample.
|
|
|
0x01 | Yes | Unknown |
0x02 | Yes | Encrypt local disks |
0x03 | Yes | Encrypt network shares |
0x04 | No | Perform language check |
0x05 | Yes | Delete volume shadow copies |
0x06 | Yes | Empty Recycle Bins |
0x07 | No | Self-delete |
0x08 | Yes | Perform UAC bypass if necessary |
0x09 | Yes | Adjust token privileges |
0x0A | Yes | Logging |
0x0B | Yes | Feature not used but results in the following
|
0x0C | Yes | Ignore specific folders |
0x0D | Yes | Ignore specific files |
0x0E | Yes | Ignore specific file extensions |
0x0F | Yes | Feature not used; related to these strings: |
0x10 | Yes | Feature not used: related to these strings: |
0x11 | Yes | Terminate processes |
0x12 | Yes | Stop services |
0x13 | Yes | Feature not used; related to a buffer that |
0x14 | Yes | Drop ransom note |
0x15 | Yes | Create a mutex |
Table 2: Configuration bits
UAC Bypass
If the malware does not have elevated privileges, it attempts to
perform one of two User Account Control (UAC) bypasses based on the
operating system (OS) version. If the OS is older than Windows 10, the
malware uses a documented
file handler hijack technique. This involves setting the
registry value
HKCU\Software\Classes\exefile\shell\open\command\Default to the
malware path and executing slui.exe using the verb "runas."
If the OS version is Windows 10 or newer, the malware attempts a
bypass that uses the CMSTPLUA COM interface. The decrypted
strings listed in Figure 7 are used to perform this technique.
Elevation:Administrator!new: |
Figure 7: Decrypted UAC bypass strings
Encryption Setup
The malware generates a pseudo-random file extension based on a MAC
address on the system. In a DARKSIDE version observed in May 2021, the
file extension is generated using a MachineGuid registry value as a
seed rather than the MAC address. The file extension consists of eight
lowercase hexadecimal characters (e.g., ".e98fc8f7") and is
referred to as <ransom_ext>. The file extension
generation algorithm has been
in Python. If logging is enabled, the malware creates the log
file LOG<ransom_ext>.TXT in its current directory.
The malware supports the command line argument "-path,"
which allows an attacker to specify a directory to target for encryption.
The sample analyzed for this report is not configured to perform a
system language check. If this functionality were enabled and the
check succeeded, the string "This is a Russian-Speaking System,
Exit" would be written to the log file and the malware would exit.
Anti-Recovery Techniques
The malware locates and empties Recycle Bins on the system. If the
process is running under WOW64, it executes the PowerShell command in
Figure 8 using CreateProcess to delete volume shadow copies.
powershell -ep bypass -c |
Figure 8: Encoded PowerShell command
The decoded command from Figure 4 is "Get-WmiObject
Win32_Shadowcopy | ForEach-Object {$_.Delete();}." If the malware
is not running under WOW64, it uses COM objects and WMI commands to
delete volume shadow copies. The decrypted strings in Figure 9 are
used to facilitate this process.
root/cimv2 |
Figure 9: Decrypted strings related to shadow
copy deletion
System Manipulation
Any service the name of which contains one of the strings listed in
Figure 10 is stopped and deleted.
vss |
Figure 10: Service-related strings
The version observed in May 2021 is additionally configured to stop
and delete services containing the strings listed in Figure 11.
GxVss |
Figure 11: Additional service-related strings in
May version
Any process name containing one of the strings listed in Figure 12
is terminated.
sql |
Figure 12: Process-related strings
File Encryption
Based on its configuration, the malware targets fixed and removable
disks as well as network shares. Some processes may be terminated so
associated files can be successfully encrypted. However, the malware
does not terminate processes listed in Figure 13.
vmcompute.exe |
Figure 13: Processes not targeted for termination
The malware uses the strings listed in Figure 14 to ignore certain
directories during the encryption process.
windows |
Figure 14: Strings used to ignore directories
The files listed in Figure 15 are ignored.
$recycle.bin |
Figure 15: Ignored files
The version observed in May 2021 is additionally configured to
ignore the files listed in Figure 16.
autorun.inf |
Figure 16: Additional ignored files in May version
Additional files are ignored based on the extensions listed in
Figure 17.
.386, .adv, .ani, .bat, .bin, |
Figure 17: Ignored file extensions
Files are encrypted using Salsa20 and a key randomly generated using
RtlRandomEx. Each key is encrypted using the embedded RSA-1024 public key.
Ransom Note
The malware writes the ransom note shown in Figure 18 to
README<ransom_ext>.TXT files written to directories it traverses.
----------- [ Welcome to Dark ] What happend? Data Example of Your personal leak page: We are ready: What guarantees? How to get access on When you open our website, put the following data in the !!! |
Figure 18: Ransom note
Decrypted Strings
| valign="top"> |
Figure 19: Decrypted strings
Yara Detections
The following YARA rules are not intended to be used on production
systems or to inform blocking rules without first being validated
through an organization's own internal testing processes to ensure
appropriate performance and limit the risk of false positives. These
rules are intended to serve as a starting point for hunting efforts to
identify related activity; however, they may need adjustment over time
if the malware family changes.
| rule |