Malicious PDF — malware analysis report

Static analysis result for SHA-256 ddb63efa57f99873…

MALICIOUS

PDF

8.1 KB
MD5: 2278002294aa80c5cb7b4dcd2b277f8a SHA-1: efde6dbaf0f9d0a657f380e2a40e935853b51589 SHA-256: ddb63efa57f99873b86e07279fa5e959ea08503fbbb751de2cf43d01283d872e
226 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1204.002 Malicious Link

The PDF file contains obfuscated JavaScript, indicated by multiple heuristic firings including 'PDF_JS_OBFUSCATED_DROPPER' and 'CVE_2007_5659'. This script is designed to download and execute a second-stage payload. The ClamAV detection 'Pdf.Exploit.Agent-35902' further confirms its malicious nature. The presence of multiple deobfuscated JavaScript files suggests a multi-stage infection process.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35902 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35902
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, incremental_eval_build, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • 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.

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
3cf6a22459cda11e607fc9e0dc0c88d01a8425e26488ff87df38d855ceb4dccf
pdf-javascript-stream PDF /JS object 5 at offset 0x148 465 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
b5b93927dfa33ffb14df9e2d77684bebaf7cfe3e8c74d260e444017c0da53701
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1B3C 1721 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
a45bd45e0b92b5ba105ac792e39584d1e719c02b8d5488efc269788ec6db820c
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x347 5090 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
ecde35472397a4bc1d50dedabca945e76231316c11a37d26513f7f3791e4f545
deobfuscated-js PDF JavaScript deobfuscation pass 24201 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).