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Vidarの台頭:広範なインフォスティーラーの活動をネットワークレイヤーで暴く

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09
Feb 2023
09
Feb 2023
2022年後半、Darktrace は顧客基盤においてVidar Stealerの感染が増加していることを確認しました。これらの感染は、コマンド&コントロール(C2)情報の取得のための特定のソーシャルメディアプラットフォームの使用や、C2通信における特定のURIパターンの使用など、予測可能な一連のネットワーク行動で構成されていました。このブログでは、これらのVidar Stealer感染で観察されたネットワーク活動のパターンの詳細と、この活動に関するDarktraceのカバレッジについて説明します。

2022年後半、Darktrace は顧客基盤においてVidar Stealerの感染が増加していることを確認しました。これらの感染は、コマンド&コントロール(C2)情報の取得のための特定のソーシャルメディアプラットフォームの使用や、C2通信における特定のURIパターンの使用など、予測可能な一連のネットワーク行動で構成されていました。このブログでは、これらのVidar Stealer感染で観察されたネットワーク活動のパターンの詳細と、この活動に関するDarktraceのカバレッジについて説明します。 

Vidar Stealerの活動背景

2018年に初めて確認されたVidar Stealerは、ユーザーのデバイスから機密データを取得し、その後流出させることができるインフォスティーラーです。このデータには、銀行の詳細、保存されたパスワード、IPアドレス、ブラウザの履歴、ログイン認証、暗号通貨ウォレットのデータなどが含まれます [1]。情報盗み出しツールは、通常、悪意のあるスパムメール、クラックされたソフトウェアのウェブサイト、悪意のある広告、正規のブランドを装ったウェブサイトを通じて配信され、ユーザーのデバイス上で実行されると、ソーシャルメディアプラットフォームのプロファイルにアクセスすることが知られています。インフォスティーラーは、このようにして、コマンド&コントロール(C2)サーバーのIPアドレスを取得します。C2サーバーのIPアドレスを取得した後、他の多くのインフォスティーラーと同様に、サードパーティーのダイナミックリンクライブラリ(DLL)をダウンロードし、感染したデバイスに保存されている機密データにアクセスするために使用することが知られています。そして、入手した機密データを束ねて、C2サーバーに送り返します。  

一連の攻撃の詳細 

2022年後半、Darktrace は多くのクライアントネットワークで次のような活動パターンを確認しました:

1. ユーザーのデバイスがTelegramおよび/またはMastodonサーバーにHTTPS接続

2. ユーザーのデバイスが、空のUser Agentヘッダー、空のHostヘッダー、4桁からなるターゲットURIを持つHTTP GETリクエストを、通常とは異なる外部のエンドポイントに行う

3. ユーザーのデバイスは、空のUser Agentヘッダー、空のHostヘッダー、および10桁の数字の後に .zip が続くターゲットURIを持つHTTP GETリクエストを、通常とは異なる外部のエンドポイントに送信

4. ユーザーのデバイスは、空のUser Agentヘッダー、空のHostヘッダー、およびターゲットURI " / " を使用して、通常とは異なる外部のエンドポイントにHTTP POSTリクエストを送信 

図1: Darktraceの Advanced Search インターフェースから取得した上記のネットワークログは、感染したデバイスが Telegram にコンタクトし、168.119.167[.]188 に一連の HTTP リクエストを行っていることを示しています
図2: Darktraceの Advanced Search インターフェースから取得した上記のネットワークログは、感染したデバイスが Mastadon サーバーに接触し、107.189.31[.]171 に一連の HTTP リクエストを行ったことを示しています。

これらの一連のアクティビティは、ユーザーがデバイス上でVidar Stealerを実行した結果、それぞれ発生したものです。ユーザーを騙してデバイス上でVidar Stealerを実行させるために使用された一般的な方法はありません。むしろ、マルスパムからクラックされたソフトウェアのダウンロードに至るまで、様々な方法が使用されたようです。 

Vidar Stealerは、ユーザーのデバイス上で実行されると、Telegram(https://t[.]me/)またはMastodonサーバー(https://nerdculture[.]de/ または https://ioc[.]exchange/)へのHTTPS接続を行います。TelegramとMastodonは、ユーザーがプロフィールを作成できるソーシャルメディアプラットフォームです。悪意のある行為者は、これらのプラットフォーム上でプロフィールを作成し、そのプロフィールの説明文にC2情報を埋め込むことが知られています[2]。 Darktraceのクライアントベースで観察されたVidarのケースでは、Vidarは、プロファイルの説明からC2サーバのIPアドレスを取得するために、Telegramおよび/またはMastodonサーバに連絡していたようです。ソーシャルメディアプラットフォームは一般的に信頼されているため、マルウェアのサンプルとC2情報を共有するこの「デッドドロップ」方式では、脅威アクターは、これらの変更の伝達をブロックされることなく、C2情報を定期的に更新することが可能になります。 

図3: Mastodonサーバーの nerdculture[.]de のプロフィールのスクリーンショット。プロフィールの説明にはC2アドレスが含まれている 

TelegramまたはMastodonプロファイルの説明からC2アドレスを取得した後、Vidarは空のUser Agentヘッダー、空のHostヘッダー、4桁からなるターゲットURIでC2サーバにHTTP GETリクエストを行いました。このURIに現れる数字の並びはキャンペーンIDです。C2サーバはVidarのGETリクエストに応答し、Vidarのその後のデータ窃取活動に影響を与えると思われる設定情報を提供しました。 

Vidarは、設定の詳細を受け取った後、空のUser Agentヘッダー、空のHostヘッダー、および10桁の数字の後に .zip が続くターゲットURIを持つGETリクエストをC2サーバに送りました。このリクエストには、vcruntime140.dll のようなサードパーティ製の正規のダイナミックリンクライブラリを含むZIPファイルが応答されました。Vidarは、これらのライブラリを使用して、感染したホスト上に保存された機密データにアクセスしました。 

図4: 上記のPCAPは、Vidarの最初のGETリクエストに応答してC2サーバーから提供されたコンフィギュレーションの詳細の例を示しています 
図5: VidarのサンプルでダウンロードしたZIPファイルに含まれるDLLの例

Vidarは、サードパーティのDLLを含むZIPファイルをダウンロードした後、C2エンドポイントに数百キロバイトのデータを含むPOSTリクエストを行いました。このPOSTリクエストは、窃取した情報の流出を意味する可能性が高いです。 

Darktrace のカバレッジ

Vidarは、ユーザーのデバイスに感染した後、TelegramまたはMastodonに連絡し、そのC2サーバに一連のHTTPリクエストを行います。このインフォスティーラーは、ソーシャルメディアプラットフォームを使用し、ツールの転送にZIPファイルを使用するため、その活動の検知を複雑にしています。しかし、このインフォスティーラーのC2サーバーへのHTTPリクエストは、以下のDarktrace DETECT/Networkモデルを侵害する原因となりました:

  • Anomalous File / Zip or Gzip from Rare External Location 
  • Anomalous File / Numeric File Download
  • Anomalous Connection / Posting HTTP to IP Without Hostname

これらのモデルブリーチは、ユーザーのデバイスが Vidar に関連することが知られている IP アドレスに接触したために発生したものではありません。実際、報告された活動が発生した時点で、接触したIPアドレスの多くは、Vidarの活動と関連付けるOSINTを持っていませんでした。これらのモデルブリーチの原因は、実際にはデバイスの HTTP アクティビティの異常さにありました。Vidar に感染したデバイスが C2 サーバーに HTTP リクエストを送信しているのが観測されたとき、Darktrace は、この動作がデバイスにとってもネットワーク内の他のデバイスにとっても非常に異例であることを認識し ました。Darktraceがこの異常性を認識したことにより、モデルブリーチが発生したのです。 

Vidar Stealerの感染は驚くほど速く、最初の感染からデータ窃取までの時間が1分未満になることもあります。Darktraceの 自律遮断技術が有効な場合、Darktrace RESPOND/Network は、最初の接続が行われた直後に、Vidar の C2 サーバーへの接続を自律的にブロックすることが可能でした。 

図6:感染したデバイスのイベントログ。デバイスが最初にC2サーバー95.217.245[.]254に接触した1秒後に、Darktrace RESPOND/Networkが自律的に介入したことを示している

結論 

2022年後半、Darktraceの顧客基盤において、特定のパターンの活動が盛んに行われ、そのパターンは幅広い業種や規模の顧客のネットワークで散見されました。さらに調査を進めると、このネットワーク活動のパターンは、Vidar Stealerの感染によるものであることが判明しました。これらの感染は、情報取得にソーシャルメディアプラットフォームを使用し、ツール転送にZIPファイルを使用するため、動きが早く、検知を回避するのに有効でした。インフォスティーラーの影響は、通常、最初の感染から時間が経過した後にネットワーク外で発生するため、インフォスティーラーの活動を十分に検知できない場合、攻撃者が知らないうちに活動し、強力な攻撃ベクトルが利用可能になって広範囲の侵害が行われる危険性があります。 

Vidar のオペレーターによる回避の試みにもかかわらず、Darktrace DETECT/Network は、Vidar の感染から必然的に生じる異常な HTTP 活動を検知することができました。Darktrace RESPOND/Networkは、このような異常な活動に対して迅速に抑制的な行動をとることができました。Vidar Stealerの普及率[3]とVidar Stealer感染の進行速度を考慮すると、自律遮断技術は情報窃盗団の活動から組織を保護するために不可欠であることが証明されています。  

本ブログに寄稿した脅威リサーチチームに感謝します。

MITRE ATT&CK マッピング

IoC一覧

107.189.31[.]171 - Vidar C2 Endpoint

168.119.167[.]188 – Vidar C2 Endpoint 

77.91.102[.]51 - Vidar C2 Endpoint

116.202.180[.]202 - Vidar C2 Endpoint

79.124.78[.]208 - Vidar C2 Endpoint

159.69.100[.]194 - Vidar C2 Endpoint

195.201.253[.]5 - Vidar C2 Endpoint

135.181.96[.]153 - Vidar C2 Endpoint

88.198.122[.]116 - Vidar C2 Endpoint

135.181.104[.]248 - Vidar C2 Endpoint

159.69.101[.]102 - Vidar C2 Endpoint

45.8.147[.]145 - Vidar C2 Endpoint

159.69.102[.]192 - Vidar C2 Endpoint

193.43.146[.]42 - Vidar C2 Endpoint

159.69.102[.]19 - Vidar C2 Endpoint

185.53.46[.]199 - Vidar C2 Endpoint

116.202.183[.]206 - Vidar C2 Endpoint

95.217.244[.]216 - Vidar C2 Endpoint

78.46.129[.]14 - Vidar C2 Endpoint

116.203.7[.]175 - Vidar C2 Endpoint

45.159.249[.]3 - Vidar C2 Endpoint

159.69.101[.]170 - Vidar C2 Endpoint

116.202.183[.]213 - Vidar C2 Endpoint

116.202.4[.]170 - Vidar C2 Endpoint

185.252.215[.]142 - Vidar C2 Endpoint

45.8.144[.]62 - Vidar C2 Endpoint

74.119.192[.]157 - Vidar C2 Endpoint

78.47.102[.]252 - Vidar C2 Endpoint

212.23.221[.]231 - Vidar C2 Endpoint

167.235.137[.]244 - Vidar C2 Endpoint

88.198.122[.]116 - Vidar C2 Endpoint

5.252.23[.]169 - Vidar C2 Endpoint

45.89.55[.]70 - Vidar C2 Endpoint

参考文献

[1] https://blog.cyble.com/2021/10/26/vidar-stealer-under-the-lens-a-deep-dive-analysis/

[2] https://asec.ahnlab.com/en/44554/

[3] https://blog.sekoia.io/unveiling-of-a-large-resilient-infrastructure-distributing-information-stealers/

INSIDE THE SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
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Roberto Romeu
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The State of AI in Cybersecurity: How AI will impact the cyber threat landscape in 2024

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22
Apr 2024

About the AI Cybersecurity Report

We surveyed 1,800 CISOs, security leaders, administrators, and practitioners from industries around the globe. Our research was conducted to understand how the adoption of new AI-powered offensive and defensive cybersecurity technologies are being managed by organizations.

This blog is continuing the conversation from our last blog post “The State of AI in Cybersecurity: Unveiling Global Insights from 1,800 Security Practitioners” which was an overview of the entire report. This blog will focus on one aspect of the overarching report, the impact of AI on the cyber threat landscape.

To access the full report click here.

Are organizations feeling the impact of AI-powered cyber threats?

Nearly three-quarters (74%) state AI-powered threats are now a significant issue. Almost nine in ten (89%) agree that AI-powered threats will remain a major challenge into the foreseeable future, not just for the next one to two years.

However, only a slight majority (56%) thought AI-powered threats were a separate issue from traditional/non AI-powered threats. This could be the case because there are few, if any, reliable methods to determine whether an attack is AI-powered.

Identifying exactly when and where AI is being applied may not ever be possible. However, it is possible for AI to affect every stage of the attack lifecycle. As such, defenders will likely need to focus on preparing for a world where threats are unique and are coming faster than ever before.

a hypothetical cyber attack augmented by AI at every stage

Are security stakeholders concerned about AI’s impact on cyber threats and risks?

The results from our survey showed that security practitioners are concerned that AI will impact organizations in a variety of ways. There was equal concern associated across the board – from volume and sophistication of malware to internal risks like leakage of proprietary information from employees using generative AI tools.

What this tells us is that defenders need to prepare for a greater volume of sophisticated attacks and balance this with a focus on cyber hygiene to manage internal risks.

One example of a growing internal risks is shadow AI. It takes little effort for employees to adopt publicly-available text-based generative AI systems to increase their productivity. This opens the door to “shadow AI”, which is the use of popular AI tools without organizational approval or oversight. Resulting security risks such as inadvertent exposure of sensitive information or intellectual property are an ever-growing concern.

Are organizations taking strides to reduce risks associated with adoption of AI in their application and computing environment?

71.2% of survey participants say their organization has taken steps specifically to reduce the risk of using AI within its application and computing environment.

16.3% of survey participants claim their organization has not taken these steps.

These findings are good news. Even as enterprises compete to get as much value from AI as they can, as quickly as possible, they’re tempering their eager embrace of new tools with sensible caution.

Still, responses varied across roles. Security analysts, operators, administrators, and incident responders are less likely to have said their organizations had taken AI risk mitigation steps than respondents in other roles. In fact, 79% of executives said steps had been taken, and only 54% of respondents in hands-on roles agreed. It seems that leaders believe their organizations are taking the needed steps, but practitioners are seeing a gap.

Do security professionals feel confident in their preparedness for the next generation of threats?

A majority of respondents (six out of every ten) believe their organizations are inadequately prepared to face the next generation of AI-powered threats.

The survey findings reveal contrasting perceptions of organizational preparedness for cybersecurity threats across different regions and job roles. Security administrators, due to their hands-on experience, express the highest level of skepticism, with 72% feeling their organizations are inadequately prepared. Notably, respondents in mid-sized organizations feel the least prepared, while those in the largest companies feel the most prepared.

Regionally, participants in Asia-Pacific are most likely to believe their organizations are unprepared, while those in Latin America feel the most prepared. This aligns with the observation that Asia-Pacific has been the most impacted region by cybersecurity threats in recent years, according to the IBM X-Force Threat Intelligence Index.

The optimism among Latin American respondents could be attributed to lower threat volumes experienced in the region, but it's cautioned that this could change suddenly (1).

What are biggest barriers to defending against AI-powered threats?

The top-ranked inhibitors center on knowledge and personnel. However, issues are alluded to almost equally across the board including concerns around budget, tool integration, lack of attention to AI-powered threats, and poor cyber hygiene.

The cybersecurity industry is facing a significant shortage of skilled professionals, with a global deficit of approximately 4 million experts (2). As organizations struggle to manage their security tools and alerts, the challenge intensifies with the increasing adoption of AI by attackers. This shift has altered the demands on security teams, requiring practitioners to possess broad and deep knowledge across rapidly evolving solution stacks.

Educating end users about AI-driven defenses becomes paramount as organizations grapple with the shortage of professionals proficient in managing AI-powered security tools. Operationalizing machine learning models for effectiveness and accuracy emerges as a crucial skill set in high demand. However, our survey highlights a concerning lack of understanding among cybersecurity professionals regarding AI-driven threats and the use of AI-driven countermeasures indicating a gap in keeping pace with evolving attacker tactics.

The integration of security solutions remains a notable problem, hindering effective defense strategies. While budget constraints are not a primary inhibitor, organizations must prioritize addressing these challenges to bolster their cybersecurity posture. It's imperative for stakeholders to recognize the importance of investing in skilled professionals and integrated security solutions to mitigate emerging threats effectively.

To access the full report click here.

参考文献

1. IBM, X-Force Threat Intelligence Index 2024, Available at: https://www.ibm.com/downloads/cas/L0GKXDWJ

2. ISC2, Cybersecurity Workforce Study 2023, Available at: https://media.isc2.org/-/media/Project/ISC2/Main/Media/ documents/research/ISC2_Cybersecurity_Workforce_Study_2023.pdf?rev=28b46de71ce24e6ab7705f6e3da8637e

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Sliver C2: How Darktrace Provided a Sliver of Hope in the Face of an Emerging C2 Framework

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17
Apr 2024

Offensive Security Tools

As organizations globally seek to for ways to bolster their digital defenses and safeguard their networks against ever-changing cyber threats, security teams are increasingly adopting offensive security tools to simulate cyber-attacks and assess the security posture of their networks. These legitimate tools, however, can sometimes be exploited by real threat actors and used as genuine actor vectors.

What is Sliver C2?

Sliver C2 is a legitimate open-source command-and-control (C2) framework that was released in 2020 by the security organization Bishop Fox. Silver C2 was originally intended for security teams and penetration testers to perform security tests on their digital environments [1] [2] [5]. In recent years, however, the Sliver C2 framework has become a popular alternative to Cobalt Strike and Metasploit for many attackers and Advanced Persistence Threat (APT) groups who adopt this C2 framework for unsolicited and ill-intentioned activities.

The use of Sliver C2 has been observed in conjunction with various strains of Rust-based malware, such as KrustyLoader, to provide backdoors enabling lines of communication between attackers and their malicious C2 severs [6]. It is unsurprising, then, that it has also been leveraged to exploit zero-day vulnerabilities, including critical vulnerabilities in the Ivanti Connect Secure and Policy Secure services.

In early 2024, Darktrace observed the malicious use of Sliver C2 during an investigation into post-exploitation activity on customer networks affected by the Ivanti vulnerabilities. Fortunately for affected customers, Darktrace DETECT™ was able to recognize the suspicious network-based connectivity that emerged alongside Sliver C2 usage and promptly brought it to the attention of customer security teams for remediation.

How does Silver C2 work?

Given its open-source nature, the Sliver C2 framework is extremely easy to access and download and is designed to support multiple operating systems (OS), including MacOS, Windows, and Linux [4].

Sliver C2 generates implants (aptly referred to as ‘slivers’) that operate on a client-server architecture [1]. An implant contains malicious code used to remotely control a targeted device [5]. Once a ‘sliver’ is deployed on a compromised device, a line of communication is established between the target device and the central C2 server. These connections can then be managed over Mutual TLS (mTLS), WireGuard, HTTP(S), or DNS [1] [4]. Sliver C2 has a wide-range of features, which include dynamic code generation, compile-time obfuscation, multiplayer-mode, staged and stageless payloads, procedurally generated C2 over HTTP(S) and DNS canary blue team detection [4].

Why Do Attackers Use Sliver C2?

Amidst the multitude of reasons why malicious actors opt for Sliver C2 over its counterparts, one stands out: its relative obscurity. This lack of widespread recognition means that security teams may overlook the threat, failing to actively search for it within their networks [3] [5].

Although the presence of Sliver C2 activity could be representative of authorized and expected penetration testing behavior, it could also be indicative of a threat actor attempting to communicate with its malicious infrastructure, so it is crucial for organizations and their security teams to identify such activity at the earliest possible stage.

Darktrace’s Coverage of Sliver C2 Activity

Darktrace’s anomaly-based approach to threat detection means that it does not explicitly attempt to attribute or distinguish between specific C2 infrastructures. Despite this, Darktrace was able to connect Sliver C2 usage to phases of an ongoing attack chain related to the exploitation of zero-day vulnerabilities in Ivanti Connect Secure VPN appliances in January 2024.

Around the time that the zero-day Ivanti vulnerabilities were disclosed, Darktrace detected an internal server on one customer network deviating from its expected pattern of activity. The device was observed making regular connections to endpoints associated with Pulse Secure Cloud Licensing, indicating it was an Ivanti server. It was observed connecting to a string of anomalous hostnames, including ‘cmjk3d071amc01fu9e10ae5rt9jaatj6b.oast[.]live’ and ‘cmjft14b13vpn5vf9i90xdu6akt5k3pnx.oast[.]pro’, via HTTP using the user agent ‘curl/7.19.7 (i686-redhat-linux-gnu) libcurl/7.63.0 OpenSSL/1.0.2n zlib/1.2.7’.

Darktrace further identified that the URI requested during these connections was ‘/’ and the top-level domains (TLDs) of the endpoints in question were known Out-of-band Application Security Testing (OAST) server provider domains, namely ‘oast[.]live’ and ‘oast[.]pro’. OAST is a testing method that is used to verify the security posture of an application by testing it for vulnerabilities from outside of the network [7]. This activity triggered the DETECT model ‘Compromise / Possible Tunnelling to Bin Services’, which breaches when a device is observed sending DNS requests for, or connecting to, ‘request bin’ services. Malicious actors often abuse such services to tunnel data via DNS or HTTP requests. In this specific incident, only two connections were observed, and the total volume of data transferred was relatively low (2,302 bytes transferred externally). It is likely that the connections to OAST servers represented malicious actors testing whether target devices were vulnerable to the Ivanti exploits.

The device proceeded to make several SSL connections to the IP address 103.13.28[.]40, using the destination port 53, which is typically reserved for DNS requests. Darktrace recognized that this activity was unusual as the offending device had never previously been observed using port 53 for SSL connections.

Model Breach Event Log displaying the ‘Application Protocol on Uncommon Port’ DETECT model breaching in response to the unusual use of port 53.
Figure 1: Model Breach Event Log displaying the ‘Application Protocol on Uncommon Port’ DETECT model breaching in response to the unusual use of port 53.

Figure 2: Model Breach Event Log displaying details pertaining to the ‘Application Protocol on Uncommon Port’ DETECT model breach, including the 100% rarity of the port usage.
Figure 2: Model Breach Event Log displaying details pertaining to the ‘Application Protocol on Uncommon Port’ DETECT model breach, including the 100% rarity of the port usage.

Further investigation into the suspicious IP address revealed that it had been flagged as malicious by multiple open-source intelligence (OSINT) vendors [8]. In addition, OSINT sources also identified that the JARM fingerprint of the service running on this IP and port (00000000000000000043d43d00043de2a97eabb398317329f027c66e4c1b01) was linked to the Sliver C2 framework and the mTLS protocol it is known to use [4] [5].

An Additional Example of Darktrace’s Detection of Sliver C2

However, it was not just during the January 2024 exploitation of Ivanti services that Darktrace observed cases of Sliver C2 usages across its customer base.  In March 2023, for example, Darktrace detected devices on multiple customer accounts making beaconing connections to malicious endpoints linked to Sliver C2 infrastructure, including 18.234.7[.]23 [10] [11] [12] [13].

Darktrace identified that the observed connections to this endpoint contained the unusual URI ‘/NIS-[REDACTED]’ which contained 125 characters, including numbers, lower and upper case letters, and special characters like “_”, “/”, and “-“, as well as various other URIs which suggested attempted data exfiltration:

‘/upload/api.html?c=[REDACTED] &fp=[REDACTED]’

  • ‘/samples.html?mx=[REDACTED] &s=[REDACTED]’
  • ‘/actions/samples.html?l=[REDACTED] &tc=[REDACTED]’
  • ‘/api.html?gf=[REDACTED] &x=[REDACTED]’
  • ‘/samples.html?c=[REDACTED] &zo=[REDACTED]’

This anomalous external connectivity was carried out through multiple destination ports, including the key ports 443 and 8888.

Darktrace additionally observed devices on affected customer networks performing TLS beaconing to the IP address 44.202.135[.]229 with the JA3 hash 19e29534fd49dd27d09234e639c4057e. According to OSINT sources, this JA3 hash is associated with the Golang TLS cipher suites in which the Sliver framework is developed [14].

結論

Despite its relative novelty in the threat landscape and its lesser-known status compared to other C2 frameworks, Darktrace has demonstrated its ability effectively detect malicious use of Sliver C2 across numerous customer environments. This included instances where attackers exploited vulnerabilities in the Ivanti Connect Secure and Policy Secure services.

While human security teams may lack awareness of this framework, and traditional rules and signatured-based security tools might not be fully equipped and updated to detect Sliver C2 activity, Darktrace’s Self Learning AI understands its customer networks, users, and devices. As such, Darktrace is adept at identifying subtle deviations in device behavior that could indicate network compromise, including connections to new or unusual external locations, regardless of whether attackers use established or novel C2 frameworks, providing organizations with a sliver of hope in an ever-evolving threat landscape.

Credit to Natalia Sánchez Rocafort, Cyber Security Analyst, Paul Jennings, Principal Analyst Consultant

付録

DETECT Model Coverage

  • Compromise / Repeating Connections Over 4 Days
  • Anomalous Connection / Application Protocol on Uncommon Port
  • Anomalous Server Activity / Server Activity on New Non-Standard Port
  • Compromise / Sustained TCP Beaconing Activity To Rare Endpoint
  • Compromise / Quick and Regular Windows HTTP Beaconing
  • Compromise / High Volume of Connections with Beacon Score
  • Anomalous Connection / Multiple Failed Connections to Rare Endpoint
  • Compromise / Slow Beaconing Activity To External Rare
  • Compromise / HTTP Beaconing to Rare Destination
  • Compromise / Sustained SSL or HTTP Increase
  • Compromise / Large Number of Suspicious Failed Connections
  • Compromise / SSL or HTTP Beacon
  • Compromise / Possible Malware HTTP Comms
  • Compromise / Possible Tunnelling to Bin Services
  • Anomalous Connection / Low and Slow Exfiltration to IP
  • Device / New User Agent
  • Anomalous Connection / New User Agent to IP Without Hostname
  • Anomalous File / EXE from Rare External Location
  • Anomalous File / Numeric File Download
  • Anomalous Connection / Powershell to Rare External
  • Anomalous Server Activity / New Internet Facing System

侵害指標(IoC)一覧

18.234.7[.]23 - Destination IP - Likely C2 Server

103.13.28[.]40 - Destination IP - Likely C2 Server

44.202.135[.]229 - Destination IP - Likely C2 Server

参考文献

[1] https://bishopfox.com/tools/sliver

[2] https://vk9-sec.com/how-to-set-up-use-c2-sliver/

[3] https://www.scmagazine.com/brief/sliver-c2-framework-gaining-traction-among-threat-actors

[4] https://github[.]com/BishopFox/sliver

[5] https://www.cybereason.com/blog/sliver-c2-leveraged-by-many-threat-actors

[6] https://securityaffairs.com/158393/malware/ivanti-connect-secure-vpn-deliver-krustyloader.html

[7] https://www.xenonstack.com/insights/out-of-band-application-security-testing

[8] https://www.virustotal.com/gui/ip-address/103.13.28.40/detection

[9] https://threatfox.abuse.ch/browse.php?search=ioc%3A107.174.78.227

[10] https://threatfox.abuse.ch/ioc/1074576/

[11] https://threatfox.abuse.ch/ioc/1093887/

[12] https://threatfox.abuse.ch/ioc/846889/

[13] https://threatfox.abuse.ch/ioc/1093889/

[14] https://github.com/projectdiscovery/nuclei/issues/3330

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著者について
Natalia Sánchez Rocafort
Cyber Security Analyst
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