What we found

• AppSecAI Vulnerability ID: 69c734eb (2 findings)
• Vulnerability: CWE-326: Inadequate Encryption
• Severity: Medium
• File: src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java:71
• Detected By: OpenGrep
• Detection Rules:
  • java.lang.security.audit.crypto.desede-is-deprecated.desede-is-deprecated
  • java.lang.security.audit.crypto.des-is-deprecated.des-is-deprecated

Description: The code uses DES (Data Encryption Standard) for symmetric encryption with the cipher transformation DES/CBC/PKCS5PADDING and key generation via KeyGenerator.getInstance("DES"). DES is cryptographically broken and deprecated by NIST. AES is the recommended replacement.

Why this matters

Risk if not fixed: DES uses a 56-bit key space, which is cryptographically broken. Exhaustive key search is feasible with modern hardware — practical attacks have been demonstrated since 1998 (DES Cracker). The code encrypts user-controlled HTTP header data and writes the result to a credentials file, making the weak cipher the sole protection boundary for sensitive values. Without adequate encryption strength, an attacker with access to the encrypted file can recover the plaintext through brute-force key recovery.

Risk level: Medium - Should be addressed in regular security maintenance. The vulnerability is confirmed and exploitable under realistic threat models (file access + computational resources).

Why we're changing it

Root cause analysis:

Lines 67–71 in BenchmarkTest02017.java explicitly instantiate DES encryption:

• Line 63: generateSeed(8) — generates an 8-byte IV matching DES's 64-bit block size
• Line 67–68: Cipher.getInstance("DES/CBC/PKCS5PADDING", java.security.Security.getProvider("SunJCE")) — DES algorithm explicitly selected
• Line 71: KeyGenerator.getInstance("DES").generateKey() — DES key generation confirms the weak cipher path

The architecture is built entirely around DES. User-controlled data from HTTP headers (lines 43–51) flows through doSomething() into the DES encryption operation at line 91 (c.doFinal(input)), then written to passwordFile.txt (lines 93–103) as encrypted output.

Why DES is inadequate:

• DES key space: 56 bits (effective) — brute-force feasible
• NIST withdrawal: Formally withdrawn in 2005 (FIPS 46-3)
• No integrity protection: CBC mode + PKCS5 padding provides confidentiality only; no authentication
• Demonstrated attacks: DES Cracker (1998) proved practical key recovery

Status: Confirmed vulnerability. Both detection rules fire on the same root cause: use of DES as the cipher algorithm.

How we confirmed

1. Traced the data flow from HTTP header input (lines 43–51) through URL decoding into the doSomething() method
2. Verified that user-controlled input becomes the plaintext for DES encryption at line 91
3. Confirmed DES algorithm selection at lines 67–68 and 71 via explicit getInstance() calls
4. Validated that the 8-byte IV (line 63) matches DES's 64-bit block size, confirming DES-specific architecture
5. Checked for compensating controls (authenticated encryption, key wrapping, integrity checks) — none present
6. Confirmed encrypted output is written to a file (lines 93–103), making the cipher strength the sole protection boundary

Vulnerability Flow Diagram

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flowchart TD
    A["HTTP Header Input<br/>(User-Controlled)"] --> B["BenchmarkTest02017.doPost<br/>Lines 43-51"]
    B --> C["URL Decode & Pass<br/>to doSomething"]
    C --> D["generateSeed8<br/>DES 64-bit IV<br/>Line 63"]
    D --> E["Cipher.getInstance<br/>'DES/CBC/PKCS5PADDING'<br/>Lines 67-68"]
    E --> F["KeyGenerator.getInstance<br/>'DES' - 56-bit key<br/>Line 71"]
    F --> G["Encrypt Plaintext<br/>c.doFinal input<br/>Line 91"]
    G --> H["Write to passwordFile.txt<br/>Lines 93-103"]
    H --> I["❌ VULNERABLE<br/>56-bit keyspace<br/>Brute-force feasible"]
    
    style A fill:#EDE9FE,stroke:#7C3AED
    style B fill:#EDE9FE,stroke:#7C3AED
    style C fill:#EDE9FE,stroke:#7C3AED
    style D fill:#FFE5E5,stroke:#F65A5A
    style E fill:#FFE5E5,stroke:#F65A5A
    style F fill:#FFE5E5,stroke:#F65A5A
    style G fill:#FFE5E5,stroke:#F65A5A
    style H fill:#FEF3C7,stroke:#F59E0B
    style I fill:#FEF3C7,stroke:#F59E0B

Vulnerable flow: src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java:71

Weak Encryption Algorithm

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flowchart TD
    subgraph Vulnerable["❌ Vulnerable Flow - CWE-326 Weak Encryption"]
        direction LR
        A1["HTTP Header Input"] --> A2["BenchmarkTest02017.doPost"
]
        A2 --> A3["generateSeed(8)
DES 64-bit block"]
        A3 --> A4["Cipher.getInstance
'DES/CBC/PKCS5PADDING'"]
        A4 --> A5["KeyGenerator
.getInstance('DES')
56-bit key"]
        A5 --> A6["💥 Brute Force Feasible
56-bit keyspace broken"]
    end

    Vulnerable ~~~ Fixed

    subgraph Fixed["✅ Fixed Flow - AES-128 Encryption"]
        direction LR
        B1["HTTP Header Input"] --> B2["BenchmarkTest02017.doPost"]
        B2 --> B3["generateSeed(16)
AES 128-bit block"]
        B3 --> B4["Cipher.getInstance
'AES/CBC/PKCS5PADDING'"]
        B4 --> B5["KeyGenerator
.getInstance('AES')
128-bit key"]
        B5 --> B6["🛡️ Brute Force Infeasible
FIPS 197 AES standard"]
    end

    style A4 fill:#FFE5E5,color:#1A1A2E
    style A5 fill:#FFE5E5,color:#1A1A2E
    style A6 fill:#ffa94d,color:#000
    style B4 fill:#74c0fc,color:#000
    style B5 fill:#74c0fc,color:#000
    style B6 fill:#DCFCE7,color:#000

How we fixed it

Fix approach: Replaced DES with AES-128 (the default key size from KeyGenerator.getInstance("AES")) using the same CBC mode and PKCS5 padding. AES uses a 128-bit block size requiring a 16-byte IV, so the seed size was updated accordingly. AES is the NIST-recommended replacement (FIPS 197) and provides 128-bit security against brute-force attacks.

Changes made:

Preservation of existing behavior:

• CBC mode and PKCS5 padding remain unchanged
• SunJCE provider remains unchanged
• All error handling paths preserved
• Encrypt-and-write flow structure unchanged
• No changes to data flow or control logic

Alternatives considered and rejected:

• AES/GCM/NoPadding: Provides authenticated encryption (AEAD) preventing ciphertext tampering; rejected to minimize change scope. Adopting GCM would require additional structural changes (GCMParameterSpec, authentication tag handling) beyond the scope of this fix.
• Triple-DES (DESede/CBC/PKCS5PADDING): Stronger than DES but still deprecated by NIST (SP 800-131A Rev. 2) and disallowed after 2023; rejected in favor of AES.
• Keeping DES with longer key: Not feasible; DES key space is fixed at 56 bits regardless of KeyGenerator output.

Vulnerabilities Addressed

• Grouped findings in scope: 2
• Findings fixed in this PR: 2
• Primary CWE family: CWE-326
• Files covered: src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java

How we validated it

1. Compilation: Code compiles without errors or warnings
2. Algorithm availability: AES is available in all Java distributions (standard JDK)
3. IV size correctness: 16-byte IV is valid for AES CBC mode (128-bit block size)
4. Key generation: KeyGenerator.getInstance("AES") generates 128-bit keys by default
5. Cipher initialization: IvParameterSpec(16-byte array) is compatible with AES CBC mode
6. Encryption/decryption: Plaintext → AES encryption → file write → read → AES decryption → plaintext recovery verified
7. No regression: Existing error handling and exception paths remain functional

How to verify

1. Confirm the cipher algorithm string changed from "DES/CBC/PKCS5PADDING" to "AES/CBC/PKCS5PADDING" at lines 67–68
2. Confirm the key generation changed from KeyGenerator.getInstance("DES") to KeyGenerator.getInstance("AES") at line 71
3. Confirm the IV seed size changed from generateSeed(8) to generateSeed(16) at line 63
4. Compile the code and verify no compilation errors
5. Run the test suite to ensure no functional regressions

#!/bin/bash
# Verification script for CWE-326 fix in BenchmarkTest02017.java
set -e

echo "=== Verification: CWE-326 Weak Encryption Algorithm Fix ==="

# Step 1: Check that DES cipher string has been replaced with AES
echo "Step 1: Verifying cipher algorithm change from DES to AES..."
if grep -q 'Cipher.getInstance("AES/CBC/PKCS5PADDING"' src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java; then
    echo "✓ Cipher algorithm correctly changed to AES/CBC/PKCS5PADDING"
else
    echo "✗ FAILED: Cipher algorithm not updated to AES/CBC/PKCS5PADDING"
    exit 1
fi

# Step 2: Check that DES key generation has been replaced with AES
echo "Step 2: Verifying key generation change from DES to AES..."
if grep -q 'KeyGenerator.getInstance("AES")' src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java; then
    echo "✓ Key generation correctly changed to AES"
else
    echo "✗ FAILED: Key generation not updated to AES"
    exit 1
fi

# Step 3: Check that IV seed size has been updated to 16 bytes for AES
echo "Step 3: Verifying IV seed size change from 8 to 16 bytes..."
if grep -q 'generateSeed(16)' src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java; then
    echo "✓ IV seed size correctly changed to 16 bytes for AES"
else
    echo "✗ FAILED: IV seed size not updated to 16 bytes"
    exit 1
fi

# Step 4: Verify no DES references remain in the cipher/key generation lines
echo "Step 4: Verifying DES algorithm references have been removed..."
if grep -E 'Cipher.getInstance\("DES' src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java; then
    echo "✗ FAILED: DES cipher reference still present"
    exit 1
else
    echo "✓ No DES cipher references found"
fi

if grep -E 'KeyGenerator.getInstance\("DES' src/main/java/org/owasp/benchmark/testcode/BenchmarkTest02017.java; then
    echo "✗ FAILED: DES key generation reference still present"
    exit 1
else
    echo "✓ No DES key generation references found"
fi

# Step 5: Compile the fixed code
echo "Step 5: Compiling fixed code..."
if mvn clean compile -q -DskipTests 2>/dev/null; then
    echo "✓ Code compiles successfully"
else
    echo "✗ FAILED: Code compilation failed"
    exit 1
fi

echo ""
echo "=== All verification checks passed ==="
exit 0

Before you merge

• Both DES references (cipher and key generation) have been replaced with AES
• IV seed size updated from 8 to 16 bytes to match AES block size
• Code compiles without errors or warnings
• No new security vulnerabilities introduced
• Existing error handling and exception paths remain functional
• Test suite passes with no regressions
• Code follows project conventions and style guidelines

Learn more

• CWE-326: Inadequate Encryption
• NIST FIPS 197: Advanced Encryption Standard (AES)
• NIST SP 800-131A Rev. 2: Transitioning the Use of Cryptographic Algorithms and Key Lengths
• DES Cracker: Practical Key Recovery (1998)

This fix was generated by AppSecAI. Please review before merging.