Malicious PDF — malware analysis report

Static analysis result for SHA-256 c292bf7ac9c5db04…

MALICIOUS

PDF

18.4 KB
MD5: c5cf270a612751db14e13f007c5d16a6 SHA-1: 01da5a3a9d49256e7e84d72c305691d03d38e5c9 SHA-256: c292bf7ac9c5db0435f545454a76aa765fda7d6a17627929ec5d35435fb6fd6a
194 Risk Score

Malware Insights

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

The PDF file contains obfuscated JavaScript, identified as a multi-stage dropper. This script is designed to exploit CVE-2007-5659, specifically targeting the Collab.collectEmailInfo function. The payload is further obfuscated using String.fromCharCode and incremental evaluation, typical of exploit kits aiming to download and execute additional malicious content. ClamAV also detected this as Pdf.Exploit.Agent-35901.

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-35901 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 4 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0009_000.js
4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
pdf-javascript-stream PDF /JS object 9 at offset 0x46F4 469 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
2e87946ec3ae0eeafa448bf1d58fc9e821fcf442685b7c788ef022406c301708
deobfuscated-js z-percent UTF-16BE base-21 decoded JavaScript at offset 0x1C18 5564 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
c0e647ffbf406f30a172091807a82335f937180c54d77b9a19d9c79288e0e118
deobfuscated-js PDF JavaScript deobfuscation pass 172486 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).