Malicious PDF — malware analysis report

Static analysis result for SHA-256 c0b932cd292d3b9e…

MALICIOUS

PDF

8.2 KB
MD5: 1524ff7ada3d32ac1b4758db13e60665 SHA-1: 33bdae01002fddc7e7778c96d50745d950d74753 SHA-256: c0b932cd292d3b9e996ecd695b15373ab451a065333acb6ab943d6a3d8e93748
194 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.002 Malicious File

This PDF file contains obfuscated JavaScript, identified by the PDF_JS_OBFUSCATED_DROPPER heuristic. The script leverages the CVE-2007-5659 vulnerability, specifically using the Collab.collectEmailInfo method to execute a decoded payload. The primary function of the script appears to be downloading and executing a second-stage payload, as indicated by the 'dropper' classification and the presence of multiple deobfuscated JavaScript files. The ClamAV detection further confirms its malicious nature.

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.Dropper.Agent-7217563-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7217563-0
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, 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
9d5c7e01faed5b04e9ec11f1d98b73f0012c871beaf60e9f9d32ad6df00d46f7
pdf-javascript-stream PDF /JS object 5 at offset 0x148 550 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
7bd9b46d3dc670f532c3872f371be0967f08a5a1404eb3e6ad92daad7742dd4b
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1B85 1780 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
347cddf30f18ae7eea42917484da62f3ca80011c6c110c500d84602eeb66cbad
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x359 5036 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
9c59041ae621d95710ce1c68d15eae8e911fe3ad12e9f6bc52d733942ff52f4b
deobfuscated-js PDF JavaScript deobfuscation pass 24456 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).