界: Input Validation and Representation

入力の検証や表現の問題は、メタキャラクター、代替エンコーディング、数値表現などによって引き起こされます。セキュリティの問題は、入力を信頼することに起因します。この問題に含まれるのは、「Buffer Overflow」、「Cross-Site Scripting」攻撃、「SQL Injection」などです。

Memcached Injection

C#/VB.NET/ASP.NET
Python

Abstract

Memcached 操作を呼び出すとき、入力が信頼できないソースからのものであれば、Memcached キャッシュに鍵と値の新しいペアを挿入することを攻撃者に許す可能性があります。

Explanation

次の場合に Memcached Injection エラーが発生します。

1. 信頼できないソースからデータがプログラムに入り込んだ場合。

2. データが Memcached の鍵または値の動的な構築に使用された場合。

例 1: 次のコードは Memcached 鍵を動的に構築します。


    ...
            TextClient tc = (TextClient)Client.GetInstance("127.0.0.1", 11211, MemcachedFlags.TextProtocol);
            tc.Open();
            string id = txtID.Text;
            var result = get_page_from_somewhere();
            var response = Http_Response(result);
            tc.Set("req-" + id, response, TimeSpan.FromSeconds(1000));
            tc.Close();
            tc = null;
    ...

このコードによって実行される操作は次のようになります。


    set req-1233 0 1000 n
    <serialized_response_instance>

ここで、n は応答の長さです。

ただし、この操作は定数の鍵プレフィックスとユーザー入力の文字列を連結して動的に構築されるため、攻撃者は文字列 ignore 0 0 1\r\n1\r\nset injected 0 3600 10\r\n0123456789\r\nset req- を送信できます。その後、操作は次のようになります。


    set req-ignore 0 0 1
    1
    set injected 0 3600 10
    0123456789
    set req-1233 0 0 n
    <serialized_response_instance>

上記の鍵はキャッシュ injected=0123456789 に新しい鍵/値のペアを追加するので、攻撃者はキャッシュを悪用できます。

References

[1] Novikov The New Page Of Injections Book: Memcached Injections

[2] Standards Mapping - Common Weakness Enumeration CWE ID 20

[3] Standards Mapping - Common Weakness Enumeration Top 25 2019 [3] CWE ID 020

[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [3] CWE ID 020

[5] Standards Mapping - Common Weakness Enumeration Top 25 2021 [4] CWE ID 020

[6] Standards Mapping - Common Weakness Enumeration Top 25 2022 [4] CWE ID 020

[7] Standards Mapping - Common Weakness Enumeration Top 25 2023 [6] CWE ID 020

[8] Standards Mapping - Common Weakness Enumeration Top 25 2024 [12] CWE ID 020

[9] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002754

[10] Standards Mapping - FIPS200 SI

[11] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data

[12] Standards Mapping - NIST Special Publication 800-53 Revision 4 SI-10 Information Input Validation (P1)

[13] Standards Mapping - NIST Special Publication 800-53 Revision 5 SI-10 Information Input Validation

[14] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.1.3 Input Validation Requirements (L1 L2 L3), 5.1.4 Input Validation Requirements (L1 L2 L3)

[15] Standards Mapping - OWASP Mobile 2024 M4 Insufficient Input/Output Validation

[16] Standards Mapping - OWASP Top 10 2004 A6 Injection Flaws

[17] Standards Mapping - OWASP Top 10 2007 A2 Injection Flaws

[18] Standards Mapping - OWASP Top 10 2010 A1 Injection

[19] Standards Mapping - OWASP Top 10 2013 A1 Injection

[20] Standards Mapping - OWASP Top 10 2017 A1 Injection

[21] Standards Mapping - OWASP Top 10 2021 A03 Injection

[22] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.6

[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.2

[24] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.1

[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.1

[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.1

[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.1

[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.1

[29] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4

[30] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 6.2.4

[31] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 4.2 - Critical Asset Protection

[32] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation

[33] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation, Control Objective C.3.2 - Web Software Attack Mitigation

[34] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I

[35] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I

[36] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I

[37] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I

[38] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I

[39] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I

[40] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I

[41] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002560 CAT I

[42] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002560 CAT I

[43] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002560 CAT I

[44] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002560 CAT I

[45] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002560 CAT I

[46] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002560 CAT I

[47] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002560 CAT I

[48] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002560 CAT I

[49] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002560 CAT I

[50] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002560 CAT I

[51] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002560 CAT I

[52] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002560 CAT I

[53] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002560 CAT I

[54] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I

[55] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I

[56] Standards Mapping - Web Application Security Consortium Version 2.00 Improper Input Handling (WASC-20)

desc.dataflow.dotnet.memcached_injection

Abstract

Explanation


...
def store(request):
    id = request.GET['id']
    result = get_page_from_somewhere()
    response = HttpResponse(result)
    cache_time = 1800
    cache.set("req-" % id, response, cache_time)
    return response
...

このコードによって実行される操作は次のようになります。


set req-1233 0 0 n
<serialized_response_instance>

ただし、この操作は定数の鍵プレフィックスとユーザー入力の文字列を連結して動的に構築されるため、攻撃者は文字列 ignore 0 0 1\r\n1\r\nset injected 0 3600 10\r\n0123456789\r\nset req- を送信できます。その後、操作は次のようになります。


set req-ignore 0 0 1
1
set injected 0 3600 10
0123456789
set req-1233 0 0 n
<serialized_response_instance>

上記の鍵はキャッシュ injected=0123456789 に鍵と値の新しいペアを追加します。ペイロードにもよりますが、攻撃者はキャッシュをポイズニングしたり、Pickle でシリアライズしたペイロードを挿入し、デシリアライゼーションのときに任意にコードを実行したりできます。