Malicious PDF — malware analysis report

Static analysis result for SHA-256 615924b44d7c4ad3…

MALICIOUS

PDF

22.8 KB Created: 2009-05-06 20:45:24 +08:00 Authoring application: DocuCom PDF Core Library
MD5: 2d6277fc5381b29d0618b90a0fbbac34 SHA-1: 7d9353be5bbf8db58c58fae48afa4b5e6eb542ec SHA-256: 615924b44d7c4ad37d4232478ac63fec16e77b165f4260fe2f178156b15bd9c8
310 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that is heavily obfuscated and utilizes unescape functions, indicating an exploit attempt. The critical heuristics 'PDF_JS_EXPLOIT_CLUSTER' and 'CLAMAV_DETECTION' strongly suggest malicious intent. The extracted JavaScript streams are likely responsible for downloading and executing a secondary payload, aligning with common exploit delivery techniques.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 9

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • ClamAV: Pdf.Exploit.Agent-35646 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35646
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/

Extracted artifacts 15

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0003_000.js
3a63aa1468610780740c9dc83aeeec5b08cb097e75c7162b2fbf08d5be27c95c
pdf-javascript-stream PDF /JS object 3 at offset 0x883 7299 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
javascript_obj0026_001.js
ca34d3015bf2d00a005095b5fa2f51491bf5aa1530f5ee8a0bf70e7f10fec374
pdf-javascript-stream PDF /JS object 26 at offset 0x20D6 14600 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: unlikely
stream_011_off000020d6.bin
49a6ae89b7a17fbad0992dde1e76ea8b7efe4849c909ce3919c991fd862c92d4
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x20D6 7299 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_000.js
7e27c9dd3f52261d7c8018838b81bf9d134d85c09f1c213544554b371747af66
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 3 at offset 0x883 5781 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_001.js
15b4247eb336bfa5c9a76e53f892cf7febc876fc4f82c2bde657708a148c6036
deobfuscated-js generic stage recovery split-literal-normalize from combined JavaScript objects at offset 0x883 20382 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_002.js
4a7af3a5f69439dc758e480d9b4a295d8fc356ebfbb6623e89e6a207136c6b59
deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x20D6 at offset 0x20D6 5781 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_003.js
5d41a6961f14341c702c65e133d441c8d420b9c7dbb42e1a9f08b42b606dd5c6
deobfuscated-js generic stage recovery split-literal-normalize -> split-literal-normalize from JavaScript object 3 at offset 0x883 5778 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_004.js
ee7394fb02b35ec856df28f2593b5311bb4a174dfa533c756dd1aa5818511382
deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from JavaScript object 3 at offset 0x883 5773 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_005.js
11b24a827fc4a119b6324022d830cc0f0eb7f50f6357c0734a2209c3c413bf2f
deobfuscated-js generic stage recovery null-collapse -> split-literal-normalize from JavaScript object 26 at offset 0x20D6 5783 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_006.js
fad5b53ea5b4ef9ae76205e1de357ecb892b5ea5432bdf2f62115c0471b3b700
deobfuscated-js generic stage recovery null-collapse -> split-literal-normalize from combined JavaScript objects at offset 0x883 11565 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 8 eval/decoder/string-building token(s).
generic_stage_recovery_007.js
7b4cf185e4ad5157b48da37469cfe3c52deeea10e1daa5aa914485718267fd87
deobfuscated-js generic stage recovery split-literal-normalize -> null-collapse from combined JavaScript objects at offset 0x883 13083 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 8 eval/decoder/string-building token(s).
generic_stage_recovery_008.js
1306f141c101dfc6927b7b893ab083ee15ef14767e1500279e085418edd2cac4
deobfuscated-js generic stage recovery split-literal-normalize -> split-literal-normalize from combined JavaScript objects at offset 0x883 20379 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_009.js
0cdc0cd407838d46b12debe9fe1cd6d4dc773133b65a034d414cfd6fba154cbe
deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from combined JavaScript objects at offset 0x883 20374 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_010.js
bcd0df201235767f762ece5c104ac424e47a00fa9b01281777853bbf9b2d362a
deobfuscated-js generic stage recovery split-literal-normalize -> split-literal-normalize from decompressed stream at 0x20D6 at offset 0x20D6 5778 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
generic_stage_recovery_011.js
cb7d0d82779fbcdf790f8058c802ef4bed7905f4266d4a163cbd22e923650c8e
deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x20D6 at offset 0x20D6 5773 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35646
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).