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SNOWYAMBER - Malware Analysis Report

High
Published: Thu Apr 13 2023 (04/13/2023, 00:00:00 UTC)
Source: CIRCL
Vendor/Project: type
Product: osint

Description

SNOWYAMBER - Malware Analysis Report

AI-Powered Analysis

AILast updated: 06/19/2025, 14:05:40 UTC

Technical Analysis

The SNOWYAMBER campaign represents a sophisticated malware operation characterized by a multi-stage attack leveraging a variety of well-known tactics, techniques, and procedures (TTPs) as classified by the MITRE ATT&CK framework. The campaign employs phishing and spearphishing (T1566, T1566.001, T1566.002) as primary initial infection vectors, utilizing malicious attachments and links that require user execution (T1204, T1204.001, T1204.002). The attackers use advanced evasion techniques such as HTML smuggling (T1027.006) and right-to-left override (T1036.002) to bypass security controls and trick users into executing malicious payloads. Once executed, the malware establishes persistence through registry run keys and startup folder modifications (T1547.001) and employs DLL search order hijacking and side-loading (T1574.001, T1574.002) to maintain stealth and evade detection. The campaign also involves infrastructure compromise (T1584) and the use of virtual private servers and web services (T1583.003, T1583.006) to host command and control (C2) infrastructure. Communication with C2 servers is conducted via web services (T1102) and one-way communication channels (T1102.003), which may limit detection opportunities. The malware also incorporates techniques to bypass the 'mark-of-the-web' security feature (T1553.005) and deobfuscate or decode files or information (T1140), indicating a high level of sophistication in payload delivery and execution. The campaign is tagged with a threat level of 1 (high) and a certainty of 50%, suggesting ongoing analysis and partial confidence in attribution and impact assessment. No patches or known exploits are currently available, indicating that mitigation relies heavily on detection and prevention strategies rather than remediation of a specific vulnerability. The campaign's use of OSINT tools and infrastructure suggests a focus on reconnaissance and targeted attacks, potentially aimed at high-value targets through spearphishing and infrastructure compromise.

Potential Impact

For European organizations, the SNOWYAMBER campaign poses significant risks primarily through targeted spearphishing attacks that can lead to credential theft, unauthorized access, and persistent malware presence within networks. The use of sophisticated evasion and persistence techniques increases the likelihood of prolonged undetected compromise, which can result in data exfiltration, intellectual property theft, and disruption of critical services. The campaign's reliance on virtual private servers and web services for C2 infrastructure complicates attribution and takedown efforts, potentially allowing attackers to maintain long-term access. Given the campaign's focus on infrastructure compromise and phishing, sectors such as government, finance, critical infrastructure, and technology are particularly vulnerable. The potential impact includes loss of confidentiality and integrity of sensitive data, operational disruption, and reputational damage. The absence of known exploits and patches means that traditional vulnerability management is insufficient, and organizations must rely on proactive detection and user awareness to mitigate risks. The campaign's use of advanced techniques like DLL side-loading and registry persistence also increases the difficulty of incident response and eradication, potentially leading to higher remediation costs and operational downtime.

Mitigation Recommendations

1. Implement advanced email filtering solutions capable of detecting and blocking spearphishing attempts, including those using HTML smuggling and obfuscated attachments or links. 2. Enforce strict execution policies such as application whitelisting to prevent unauthorized execution of malicious files, especially those leveraging DLL side-loading and search order hijacking. 3. Deploy endpoint detection and response (EDR) tools with behavioral analytics to identify persistence mechanisms like registry run keys and startup folder modifications. 4. Conduct regular user training focused on recognizing sophisticated phishing techniques, including the risks of right-to-left override and mark-of-the-web bypass tactics. 5. Monitor network traffic for anomalous web service communications and one-way communication patterns indicative of C2 activity, using threat intelligence feeds to identify known SNOWYAMBER infrastructure. 6. Restrict use of virtual private servers and closely monitor any external infrastructure interactions to detect potential compromise or unauthorized use. 7. Implement robust incident response plans that include procedures for detecting and removing DLL hijacking and side-loading malware components. 8. Utilize threat hunting exercises focused on MITRE ATT&CK techniques associated with SNOWYAMBER to proactively identify indicators of compromise. 9. Maintain up-to-date OSINT and threat intelligence to adapt defenses as new information about the campaign emerges. 10. Apply network segmentation and least privilege principles to limit lateral movement and reduce the impact of potential breaches.

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Technical Details

Threat Level
1
Analysis
0
Uuid
68cf0b2c-e449-4b2e-a7f7-b2b55cf951b5
Original Timestamp
1681739653

Indicators of Compromise

File

ValueDescriptionCopy
filePhishMailImpers1.png
phishing email mimicking diplomatic correspondence. The link hidden under “here” leads to the ENVYSCOUT
fileSNOWYAMBER_.pdf
filevcruntime140.dll
fileschedule.zip
file7za.dll
filenovember_schedulexe.pdf
fileInstructions.lnk
fileBugSplatRc64.dll
fileBugSplatRc64.dll
filehXaIk1725.pdf
filehXaIk1314.pdf

Url

ValueDescriptionCopy
urltotalmassasje.no/schedule.php
ENVYSCOUT delivering SNOWYAMBER ZIP
urlsignitivelogics.com/Schedule.html
ENVYSCOUT delivering SNOWYAMBER ISO
urlhumanecosmetics.com/category/noteworthy/6426-7346-9789
Cobalt Strike Team Server
urlsignitivelogics.com/BMW.html
ENVYSCOUT delivering SNOWYAMBER ISO
urlliteraturaelsalvador.com/Instructions.html
ENVYSCOUT delivering SNOWYAMBER ZIP
urlliteraturaelsalvador.com/Schedule.html
ENVYSCOUT delivering SNOWYAMBER ISO
urlparquesanrafael.cl/note.html
ENVYSCOUT URL
urlinovaoftalmologia.com.br/form.html
ENVYSCOUT URL

Domain

ValueDescriptionCopy
domainbadriatimimi.com
BRUTERATEL C2

Email

ValueDescriptionCopy
emailmiodrag.sekulic@mod.gov.rs
Used to distribute phishing emails with a link to ENVYSCOUT
emailbohuslava.kopalova@seznam.cz
Used to distribute phishing emails with a link to ENVYSCOUT
emailnavratilova.lucie.etnologie@seznam.cz
Used to distribute phishing emails with a link to i.php (reconnaissance?)
emailzdenek.holych@seznam.cz
Used to distribute phishing emails with a link to ENVYSCOUT

Link

ValueDescriptionCopy
linkhttps://www.gov.pl/attachment/ee91f24d-3e67-436d-aa50-7fa56acf789d

Text

ValueDescriptionCopy
textSNOWYAMBER is a dropper that was used in an espionage campaign significantly overlapping with publicly described activity linked to the APT29 and NOBELIUM activity sets. SNOWYAMBER abuses the NOTION collaboration service as a communication channel. It does not contain any other capabilities aside from downloading and executing 2nd stage. To bypass security products, SNOWYAMBER uses several antidetection and obfuscation techniques, including string encryption, dynamic API resolving, EDR/AV unhooking, and direct syscalls.
textReport
textAPT29_SNOWYAMBER

Size in-bytes

ValueDescriptionCopy
size-in-bytes270336
size-in-bytes271360
size-in-bytes301056
size-in-bytes261635
size-in-bytes347837

Hash

ValueDescriptionCopy
hashc938934c0f5304541087313382aee163e0c5239c
hashd0efe94196b4923eb644ec0b53d226cc
hash381a3c6c7e119f58dfde6f03a9890353a20badfa1bfa7c38ede62c6b0692103c
hash8eb64670c10505322d45f6114bc9f7de0826e3a1
hashcf36bf564fbb7d5ec4cec9b0f185f6c9
hashe957326b2167fa7ccd508cbf531779a28bfce75eb2635ab81826a522979aeb98
hash3fd43de3c9f7609c52da71c1fc4c01ce0b5ac74c
hash82ecb8474efe5fedcb8f57b8aafa93d2
hash4d92a4cecb62d237647a20d2cdfd944d5a29c1a14b274d729e9c8ccca1f0b68b
hashaaf973a56b17a0a82cf1b3a49ff68da1c50283d4
hash800db035f9b6f1e86a7f446a8a8e3947
hash032855b043108967a6c2de154624c16b70a0b7d0d0a0e93064b387f59537cc1e
hasha8a82a7da2979b128cbeddf4e70f9d5725ef666b
hash0e594576bb36b025e80eab7c35dc885e
hashec687a447ca036b10c28c1f9e1e9cef9f2078fdbc2ffdb4d8dd32e834b310c0d

Yara

ValueDescriptionCopy
yararule APT29_SNOWYAMBER { meta: description = "Detects APT29-linked SNOWYAMBER dropper" strings: // Payload decryption loop // Custom algorithm based on XOR $op_decrypt_payload = {49 8B 45 08 48 ?? ?? ?? 48 39 ?? 76 2B 48 89 C8 31 D2 4C 8B 4C 24 ?? 48 F7 74 24 ?? 49 8B 45 00 41 8A 14 11 32 54 08 10 89 C8 41 0F AF C0 31 C2 88 14 0B 48 FF C1} // Decryption routine generated by Obfuscate library $op_decrypt_string = {48 39 D0 74 19 48 89 C1 4D 89 C2 83 E1 07 48 C1 E1 03 49 D3 EA 45 30 14 01 48 FF C0 EB E2} // Hardcoded inital value used as beaconing counter $op_initialize_emoji = {C6 [3] A5 66 [4] F0 9F} // src/json.hpp - string left in binary using nlohmann JSON $str_nlohmann = {73 72 63 2F 6A 73 6F 6E 2E 68 70 70 00} condition: uint16(0) == 0x5A4D and filesize < 500KB and $str_nlohmann and $op_decrypt_string and ($op_initialize_emoji or $op_decrypt_payload) }

Threat ID: 682c7adae3e6de8ceb777c09

Added to database: 5/20/2025, 12:51:38 PM

Last enriched: 6/19/2025, 2:05:40 PM

Last updated: 8/13/2025, 3:33:05 PM

Views: 9

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