Malicious PDF — malware analysis report

Static analysis result for SHA-256 5a533b102ae54c4f…

MALICIOUS

PDF

9.9 KB
MD5: 26fce5e872a94fb720e0b367f1f96924 SHA-1: 10b3eafc468d7da9159033e7dd2640af5bbc7fc3 SHA-256: 5a533b102ae54c4f83dccaa7d90a5817d1bc83d97782b563b7298d8106b83729
278 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The sample is a PDF file that leverages JavaScript to exploit CVE-2007-5659, specifically targeting Adobe Reader versions within a certain patch range. The embedded JavaScript contains a URL that is used to download a second-stage payload. The script reconstructs the URL from obfuscated parts and uses `eval` to execute it, indicating a downloader functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 10

  • 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)
  • Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE
    PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
  • 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.
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • 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.
  • 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://google.analytics.com.zelhnalbivd.info/nte/avorp1kav1%20.asp/eU230d9c2eH0298087eV03007f35002Raacc4fdc102Td894469cQ000002fd901801F002a000aJ0b000601l0409K11fafc2f

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
9f17df95bc71874fe0f2dcb9f0e8f529cdb3604910d27079f2fbde52cabda2a8
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 256 bytes
generic_stage_recovery_000.js
6c29f58cd24a1c109c3171cedc5243aa6196e7e1029a40931b7f7192717d4139
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19B 246 bytes
annotation_subject_callee_hex_stage_000.js
70cae68b09cb6de79816a92bb1be9859d0c45aed76424014555a47cf58e5a0ac
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5378 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
676f235e5495bb6c9009012bb921120de2f0b0ff73ea1f6ba70b0ed2823edbc4
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D0 12706 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
57ff53002f97bb142cb3becb069deb114206c7b427620e63c0a8bbf62b3d805e
deobfuscated-js PDF JavaScript deobfuscation pass 68624 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).